Initial revision

1 files changed, 326 insertions, 0 deletions

diff --git a/gc/ptr_chck.c b/gc/ptr_chck.c
new file mode 100644
index 0000000..f3451ee
--- /dev/null
+++ b/gc/ptr_chck.c
@@ -0,0 +1,326 @@
+/* 
+ * 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"
+
+#ifdef __STDC__
+void GC_default_same_obj_print_proc(GC_PTR p, GC_PTR q)
+#else
+void GC_default_same_obj_print_proc (p, q)
+GC_PTR p, q;
+#endif
+{
+    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_PROTO((GC_PTR, GC_PTR))
+		= 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);
+}
+
+#ifdef __STDC__
+void GC_default_is_valid_displacement_print_proc (GC_PTR p)
+#else
+void GC_default_is_valid_displacement_print_proc (p)
+GC_PTR p;
+#endif
+{
+    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_PROTO((GC_PTR)) = 
+	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);
+}
+
+#ifdef __STDC__
+void GC_default_is_visible_print_proc(GC_PTR p)
+#else
+void GC_default_is_visible_print_proc(p)
+GC_PTR p;
+#endif
+{
+    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_PROTO((GC_PTR p)) = 
+	GC_default_is_visible_print_proc;
+
+/* Could p be a stack address? */
+GC_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) {
+    	    GC_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);
+}