summaryrefslogtreecommitdiff
path: root/ptr_chck.c
diff options
context:
space:
mode:
authorIvan Maidanski <ivmai@mail.ru>2011-07-26 12:51:28 +0200
committerIvan Maidanski <ivmai@mail.ru>2011-07-26 12:51:28 +0200
commitacf2e57f2091522924a0064b318642253e2b2bac (patch)
tree81d1d9fe63ae4d7b109b494d171ac33bc361c803 /ptr_chck.c
parent7fd4efa1d0dbab63e6d9bddd1d72fa4aafc8ad52 (diff)
gc4.8 tarball importgc4_8
Diffstat (limited to 'ptr_chck.c')
-rw-r--r--ptr_chck.c315
1 files changed, 315 insertions, 0 deletions
diff --git a/ptr_chck.c b/ptr_chck.c
new file mode 100644
index 0000000..4d2cc8b
--- /dev/null
+++ b/ptr_chck.c
@@ -0,0 +1,315 @@
+/*
+ * 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 19, 1995 1:26 pm PDT */
+
+#include "gc_priv.h"
+#include "gc_mark.h"
+
+void GC_default_same_obj_print_proc(p,q)
+ptr_t p, q;
+{
+ GC_err_printf2("0x%lx and 0x%lx are not in the same object\n",
+ (unsigned long)p, (unsigned long)q);
+ ABORT("GC_same_obj test failed");
+}
+
+void (*GC_same_obj_print_proc)() = GC_default_same_obj_print_proc;
+
+/* Check that p and q point to the same object. Call */
+/* *GC_same_obj_print_proc if they don't. */
+/* Returns the first argument. (Return value may be hard */
+/* to use,due to typing issues. But if we had a suitable */
+/* preprocessor ...) */
+/* Succeeds if neither p nor q points to the heap. */
+/* We assume this is performance critical. (It shouldn't */
+/* be called by production code, but this can easily make */
+/* debugging intolerably slow.) */
+#ifdef __STDC__
+ GC_PTR GC_same_obj(register void *p, register void *q)
+#else
+ GC_PTR GC_same_obj(p, q)
+ register char *p, *q;
+#endif
+{
+ register struct hblk *h;
+ register hdr *hhdr;
+ register ptr_t base, limit;
+ register word sz;
+
+ if (!GC_is_initialized) GC_init();
+ hhdr = HDR((word)p);
+ if (hhdr == 0) {
+ if (divHBLKSZ((word)p) != divHBLKSZ((word)q)
+ && HDR((word)q) != 0) {
+ goto fail;
+ }
+ return(p);
+ }
+ /* If it's a pointer to the middle of a large object, move it */
+ /* to the beginning. */
+ if (IS_FORWARDING_ADDR_OR_NIL(hhdr)) {
+ h = HBLKPTR(p) - (word)hhdr;
+ hhdr = HDR(h);
+ while (IS_FORWARDING_ADDR_OR_NIL(hhdr)) {
+ h = FORWARDED_ADDR(h, hhdr);
+ hhdr = HDR(h);
+ }
+ limit = (ptr_t)((word *)h + HDR_WORDS + hhdr -> hb_sz);
+ if ((ptr_t)p >= limit || (ptr_t)q >= limit || (ptr_t)q < (ptr_t)h ) {
+ goto fail;
+ }
+ return(p);
+ }
+ sz = WORDS_TO_BYTES(hhdr -> hb_sz);
+ if (sz > WORDS_TO_BYTES(MAXOBJSZ)) {
+ base = (ptr_t)HBLKPTR(p);
+ limit = base + sz;
+ if ((ptr_t)p >= limit) {
+ goto fail;
+ }
+ } else {
+# ifdef ALL_INTERIOR_POINTERS
+ register map_entry_type map_entry;
+ register int pdispl;
+
+ pdispl = HBLKDISPL(p);
+ map_entry = MAP_ENTRY((hhdr -> hb_map), pdispl);
+ if (map_entry == OBJ_INVALID) {
+ goto fail;
+ } else {
+ base = (char *)((word)p & ~(WORDS_TO_BYTES(1) - 1));
+ base -= WORDS_TO_BYTES(map_entry);
+ }
+# else
+ register int offset = HBLKDISPL(p) - HDR_BYTES;
+ register word correction = offset % sz;
+
+ if (HBLKPTR(p) != HBLKPTR(q)) {
+ /* The following computation otherwise fails in this case */
+ goto fail;
+ }
+ base = (ptr_t)p - correction;
+# endif
+ limit = base + sz;
+ }
+ /* [base, limit) delimits the object containing p, if any. */
+ /* If p is not inside a valid object, then either q is */
+ /* also outside any valid object, or it is outside */
+ /* [base, limit). */
+ if ((ptr_t)q >= limit || (ptr_t)q < base) {
+ goto fail;
+ }
+ return(p);
+fail:
+ (*GC_same_obj_print_proc)((ptr_t)p, (ptr_t)q);
+ return(p);
+}
+
+
+void GC_default_is_valid_displacement_print_proc(p)
+ptr_t p;
+{
+ GC_err_printf1("0x%lx does not point to valid object displacement\n",
+ (unsigned long)p);
+ ABORT("GC_is_valid_displacement test failed");
+}
+
+void (*GC_is_valid_displacement_print_proc)() =
+ GC_default_is_valid_displacement_print_proc;
+
+/* Check that if p is a pointer to a heap page, then it points to */
+/* a valid displacement within a heap object. */
+/* Uninteresting with ALL_INTERIOR_POINTERS. */
+/* Always returns its argument. */
+/* Note that we don't lock, since nothing relevant about the header */
+/* should change while we have a valid object pointer to the block. */
+#ifdef __STDC__
+ void * GC_is_valid_displacement(void *p)
+#else
+ char *GC_is_valid_displacement(p)
+ char *p;
+#endif
+{
+ register hdr *hhdr;
+ register word pdispl;
+ register struct hblk *h;
+ register map_entry_type map_entry;
+ register word sz;
+
+ if (!GC_is_initialized) GC_init();
+ hhdr = HDR((word)p);
+ if (hhdr == 0) return(p);
+ h = HBLKPTR(p);
+# ifdef ALL_INTERIOR_POINTERS
+ while (IS_FORWARDING_ADDR_OR_NIL(hhdr)) {
+ h = FORWARDED_ADDR(h, hhdr);
+ hhdr = HDR(h);
+ }
+# endif
+ if (IS_FORWARDING_ADDR_OR_NIL(hhdr)) {
+ goto fail;
+ }
+ sz = WORDS_TO_BYTES(hhdr -> hb_sz);
+ pdispl = HBLKDISPL(p);
+ map_entry = MAP_ENTRY((hhdr -> hb_map), pdispl);
+ if (map_entry == OBJ_INVALID
+ || sz > MAXOBJSZ && (ptr_t)p >= (ptr_t)h + sz) {
+ goto fail;
+ }
+ return(p);
+fail:
+ (*GC_is_valid_displacement_print_proc)((ptr_t)p);
+ return(p);
+}
+
+
+void GC_default_is_visible_print_proc(p)
+ptr_t p;
+{
+ GC_err_printf1("0x%lx is not a GC visible pointer location\n",
+ (unsigned long)p);
+ ABORT("GC_is_visible test failed");
+}
+
+void (*GC_is_visible_print_proc)() =
+ GC_default_is_visible_print_proc;
+
+/* Could p be a stack address? */
+bool GC_on_stack(p)
+ptr_t p;
+{
+# ifdef THREADS
+ return(TRUE);
+# else
+ int dummy;
+# ifdef STACK_GROWS_DOWN
+ if ((ptr_t)p >= (ptr_t)(&dummy) && (ptr_t)p < GC_stackbottom ) {
+ return(TRUE);
+ }
+# else
+ if ((ptr_t)p <= (ptr_t)(&dummy) && (ptr_t)p > GC_stackbottom ) {
+ return(TRUE);
+ }
+# endif
+ return(FALSE);
+# endif
+}
+
+/* Check that p is visible */
+/* to the collector as a possibly pointer containing location. */
+/* If it isn't invoke *GC_is_visible_print_proc. */
+/* Returns the argument in all cases. May erroneously succeed */
+/* in hard cases. (This is intended for debugging use with */
+/* untyped allocations. The idea is that it should be possible, though */
+/* slow, to add such a call to all indirect pointer stores.) */
+/* Currently useless for multithreaded worlds. */
+#ifdef __STDC__
+ void * GC_is_visible(void *p)
+#else
+ char *GC_is_visible(p)
+ char *p;
+#endif
+{
+ register hdr *hhdr;
+
+ if ((word)p & (ALIGNMENT - 1)) goto fail;
+ if (!GC_is_initialized) GC_init();
+# ifdef THREADS
+ hhdr = HDR((word)p);
+ if (hhdr != 0 && GC_base(p) == 0) {
+ goto fail;
+ } else {
+ /* May be inside thread stack. We can't do much. */
+ return(p);
+ }
+# else
+ /* Check stack first: */
+ if (GC_on_stack(p)) return(p);
+ hhdr = HDR((word)p);
+ if (hhdr == 0) {
+ bool result;
+
+ if (GC_is_static_root(p)) return(p);
+ /* Else do it again correctly: */
+# if (defined(DYNAMIC_LOADING) || defined(MSWIN32) || defined(PCR)) \
+ && !defined(SRC_M3)
+ DISABLE_SIGNALS();
+ GC_register_dynamic_libraries();
+ result = GC_is_static_root(p);
+ ENABLE_SIGNALS();
+ if (result) return(p);
+# endif
+ goto fail;
+ } else {
+ /* p points to the heap. */
+ word descr;
+ ptr_t base = GC_base(p); /* Should be manually inlined? */
+
+ if (base == 0) goto fail;
+ if (HBLKPTR(base) != HBLKPTR(p)) hhdr = HDR((word)p);
+ descr = hhdr -> hb_descr;
+ retry:
+ switch(descr & DS_TAGS) {
+ case DS_LENGTH:
+ if ((word)((ptr_t)p - (ptr_t)base) > (word)descr) goto fail;
+ break;
+ case DS_BITMAP:
+ if ((ptr_t)p - (ptr_t)base
+ >= WORDS_TO_BYTES(BITMAP_BITS)
+ || ((word)p & (sizeof(word) - 1))) goto fail;
+ if (!((1 << (WORDSZ - ((ptr_t)p - (ptr_t)base) - 1))
+ & descr)) goto fail;
+ break;
+ case DS_PROC:
+ /* We could try to decipher this partially. */
+ /* For now we just punt. */
+ break;
+ case DS_PER_OBJECT:
+ descr = *(word *)((ptr_t)base + (descr & ~DS_TAGS));
+ goto retry;
+ }
+ return(p);
+ }
+# endif
+fail:
+ (*GC_is_visible_print_proc)((ptr_t)p);
+ return(p);
+}
+
+
+GC_PTR GC_pre_incr (p, how_much)
+GC_PTR *p;
+size_t how_much;
+{
+ GC_PTR initial = *p;
+ GC_PTR result = GC_same_obj((GC_PTR)((word)initial + how_much), initial);
+
+# ifndef ALL_INTERIOR_POINTERS
+ (void) GC_is_valid_displacement(result);
+# endif
+ return (*p = result);
+}
+
+GC_PTR GC_post_incr (p, how_much)
+GC_PTR *p;
+size_t how_much;
+{
+ GC_PTR initial = *p;
+ GC_PTR result = GC_same_obj((GC_PTR)((word)initial + how_much), initial);
+
+# ifndef ALL_INTERIOR_POINTERS
+ (void) GC_is_valid_displacement(result);
+# endif
+ *p = result;
+ return(initial);
+}