boehm-gc/ptr_chck.c - native_client/nacl-gcc - Git at Google

 /*
  * 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.
  */

 /*
  * These are checking routines calls to which could be inserted by a
  * preprocessor to validate C pointer arithmetic.
  */

 #include "private/gc_pmark.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 + 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 > MAXOBJBYTES) {
       base = (ptr_t)HBLKPTR(p);
       limit = base + sz;
       if ((ptr_t)p >= limit) {
         goto fail;
       }
     } else {
       register int map_entry;
       register int pdispl = HBLKDISPL(p);

       map_entry = MAP_ENTRY((hhdr -> hb_map), pdispl);
       if (map_entry > CPP_MAX_OFFSET) {
          map_entry = BYTES_TO_WORDS(pdispl) % BYTES_TO_WORDS(sz);
 	 if (HBLKPTR(p) != HBLKPTR(q)) goto fail;
 	 	/* W/o this check, we might miss an error if 	*/
 	 	/* q points to the first object on a page, and	*/
 	 	/* points just before the page.			*/
       }
       base = (char *)((word)p & ~(WORDS_TO_BYTES(1) - 1));
       base -= WORDS_TO_BYTES(map_entry);
       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 GC_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);
     if (GC_all_interior_pointers) {
 	while (IS_FORWARDING_ADDR_OR_NIL(hhdr)) {
 	   h = FORWARDED_ADDR(h, hhdr);
 	   hhdr = HDR(h);
 	}
     }
     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 > MAXOBJBYTES && (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(MSWINCE) || defined (CYGWIN32) || 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 & GC_DS_TAGS) {
     	        case GC_DS_LENGTH:
     	            if ((word)((ptr_t)p - (ptr_t)base) > (word)descr) goto fail;
     	            break;
     	        case GC_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 GC_DS_PROC:
     	            /* We could try to decipher this partially. 	*/
     	            /* For now we just punt.				*/
     	            break;
     	        case GC_DS_PER_OBJECT:
 		    if ((signed_word)descr >= 0) {
     	              descr = *(word *)((ptr_t)base + (descr & ~GC_DS_TAGS));
 		    } else {
 		      ptr_t type_descr = *(ptr_t *)base;
 		      descr = *(word *)(type_descr
 			      - (descr - (GC_DS_PER_OBJECT
 					  - GC_INDIR_PER_OBJ_BIAS)));
 		    }
     	            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);

     if (!GC_all_interior_pointers) {
     	(void) GC_is_valid_displacement(result);
     }
     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);

     if (!GC_all_interior_pointers) {
     	(void) GC_is_valid_displacement(result);
     }
     *p = result;
     return(initial);
 }
	/*
	* 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.
	*/

	/*
	* These are checking routines calls to which could be inserted by a
	* preprocessor to validate C pointer arithmetic.
	*/

	#include "private/gc_pmark.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 + 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 > MAXOBJBYTES) {
	base = (ptr_t)HBLKPTR(p);
	limit = base + sz;
	if ((ptr_t)p >= limit) {
	goto fail;
	}
	} else {
	register int map_entry;
	register int pdispl = HBLKDISPL(p);

	map_entry = MAP_ENTRY((hhdr -> hb_map), pdispl);
	if (map_entry > CPP_MAX_OFFSET) {
	map_entry = BYTES_TO_WORDS(pdispl) % BYTES_TO_WORDS(sz);
	if (HBLKPTR(p) != HBLKPTR(q)) goto fail;
	/* W/o this check, we might miss an error if */
	/* q points to the first object on a page, and */
	/* points just before the page. */
	}
	base = (char *)((word)p & ~(WORDS_TO_BYTES(1) - 1));
	base -= WORDS_TO_BYTES(map_entry);
	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 GC_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);
	if (GC_all_interior_pointers) {
	while (IS_FORWARDING_ADDR_OR_NIL(hhdr)) {
	h = FORWARDED_ADDR(h, hhdr);
	hhdr = HDR(h);
	}
	}
	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 > MAXOBJBYTES && (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(MSWINCE) \|\| defined (CYGWIN32) \|\| 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 & GC_DS_TAGS) {
	case GC_DS_LENGTH:
	if ((word)((ptr_t)p - (ptr_t)base) > (word)descr) goto fail;
	break;
	case GC_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 GC_DS_PROC:
	/* We could try to decipher this partially. */
	/* For now we just punt. */
	break;
	case GC_DS_PER_OBJECT:
	if ((signed_word)descr >= 0) {
	descr = (word )((ptr_t)base + (descr & ~GC_DS_TAGS));
	} else {
	ptr_t type_descr = (ptr_t )base;
	descr = (word )(type_descr
	- (descr - (GC_DS_PER_OBJECT
	- GC_INDIR_PER_OBJ_BIAS)));
	}
	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);

	if (!GC_all_interior_pointers) {
	(void) GC_is_valid_displacement(result);
	}
	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);

	if (!GC_all_interior_pointers) {
	(void) GC_is_valid_displacement(result);
	}
	*p = result;
	return(initial);
	}