boehm-gc/gcj_mlc.c

/*
 * Copyright (c) 1991-1994 by Xerox Corporation.  All rights reserved.
 * Copyright (c) 1999 by Hewlett-Packard Company.  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, July 31, 1995 5:02 pm PDT */

/*
 * This is an allocator interface tuned for gcj (the GNU static
 * java compiler).
 *
 * Each allocated object has a pointer in its first word to a vtable,
 * which for our purposes is simply a structure describing the type of
 * the object.
 * This descriptor structure contains a GC marking descriptor at offset
 * MARK_DESCR_OFFSET.
 *
 * It is hoped that this interface may also be useful for other systems,
 * possibly with some tuning of the constants.  But the immediate goal
 * is to get better gcj performance.
 *
 * We assume:
 *  1) We have an ANSI conforming C compiler.
 *  2) Counting on explicit initialization of this interface is OK.
 *  3) FASTLOCK is not a significant win.
 */

#include "private/gc_pmark.h"
#include "gc_gcj.h"
#include "private/dbg_mlc.h"

#ifdef GC_GCJ_SUPPORT

GC_bool GC_gcj_malloc_initialized = FALSE;

int GC_gcj_kind;	/* Object kind for objects with descriptors     */
			/* in "vtable".					*/
int GC_gcj_debug_kind;	/* The kind of objects that is always marked 	*/
			/* with a mark proc call.			*/

ptr_t * GC_gcjobjfreelist;
ptr_t * GC_gcjdebugobjfreelist;

/* Caller does not hold allocation lock. */
void GC_init_gcj_malloc(int mp_index, void * /* really GC_mark_proc */mp)
{
    register int i;
    GC_bool ignore_gcj_info;
    DCL_LOCK_STATE;

    GC_init();	/* In case it's not already done.	*/
    DISABLE_SIGNALS();
    LOCK();
    if (GC_gcj_malloc_initialized) {
      UNLOCK();
      ENABLE_SIGNALS();
      return;
    }
    GC_gcj_malloc_initialized = TRUE;
    ignore_gcj_info = (0 != GETENV("GC_IGNORE_GCJ_INFO"));
#   ifdef CONDPRINT
      if (GC_print_stats && ignore_gcj_info) {
        GC_printf0("Gcj-style type information is disabled!\n");
      }
#   endif
    GC_ASSERT(GC_mark_procs[mp_index] == (GC_mark_proc)0); /* unused */
    GC_mark_procs[mp_index] = (GC_mark_proc)mp;
    if (mp_index >= GC_n_mark_procs) ABORT("GC_init_gcj_malloc: bad index");
    /* Set up object kind gcj-style indirect descriptor. */
      GC_gcjobjfreelist = (ptr_t *)GC_new_free_list_inner();
      if (ignore_gcj_info) {
	/* Use a simple length-based descriptor, thus forcing a fully	*/
	/* conservative scan.						*/
	GC_gcj_kind = GC_new_kind_inner((void **)GC_gcjobjfreelist,
					(0 | GC_DS_LENGTH),
				        TRUE, TRUE);
      } else {
	GC_gcj_kind = GC_new_kind_inner(
			(void **)GC_gcjobjfreelist,
			(((word)(-MARK_DESCR_OFFSET - GC_INDIR_PER_OBJ_BIAS))
	   		 | GC_DS_PER_OBJECT),
			FALSE, TRUE);
      }
    /* Set up object kind for objects that require mark proc call.	*/
      if (ignore_gcj_info) {
	GC_gcj_debug_kind = GC_gcj_kind;
        GC_gcjdebugobjfreelist = GC_gcjobjfreelist;
      } else {
        GC_gcjdebugobjfreelist = (ptr_t *)GC_new_free_list_inner();
	GC_gcj_debug_kind = GC_new_kind_inner(
				(void **)GC_gcjdebugobjfreelist,
				GC_MAKE_PROC(mp_index,
				     	     1 /* allocated with debug info */),
				FALSE, TRUE);
      }
    UNLOCK();
    ENABLE_SIGNALS();
}

ptr_t GC_clear_stack();

#define GENERAL_MALLOC(lb,k) \
    (GC_PTR)GC_clear_stack(GC_generic_malloc_inner((word)lb, k))
    
#define GENERAL_MALLOC_IOP(lb,k) \
    (GC_PTR)GC_clear_stack(GC_generic_malloc_inner_ignore_off_page(lb, k))

/* We need a mechanism to release the lock and invoke finalizers.	*/
/* We don't really have an opportunity to do this on a rarely executed	*/
/* path on which the lock is not held.  Thus we check at a 		*/
/* rarely executed point at which it is safe to release the lock.	*/
/* We do this even where we could just call GC_INVOKE_FINALIZERS,	*/
/* since it's probably cheaper and certainly more uniform.		*/
/* FIXME - Consider doing the same elsewhere?				*/
static void maybe_finalize()
{
   static int last_finalized_no = 0;

   if (GC_gc_no == last_finalized_no) return;
   if (!GC_is_initialized) return;
   UNLOCK();
   GC_INVOKE_FINALIZERS();
   last_finalized_no = GC_gc_no;
   LOCK();
}

/* Allocate an object, clear it, and store the pointer to the	*/
/* type structure (vtable in gcj).				*/
/* This adds a byte at the end of the object if GC_malloc would.*/
void * GC_gcj_malloc(size_t lb, void * ptr_to_struct_containing_descr)
{
register ptr_t op;
register ptr_t * opp;
register word lw;
DCL_LOCK_STATE;

    if( EXPECT(SMALL_OBJ(lb), 1) ) {
#       ifdef MERGE_SIZES
	  lw = GC_size_map[lb];
#	else
	  lw = ALIGNED_WORDS(lb);
#       endif
	opp = &(GC_gcjobjfreelist[lw]);
	LOCK();
	op = *opp;
        if(EXPECT(op == 0, 0)) {
	    maybe_finalize();
            op = (ptr_t)GENERAL_MALLOC((word)lb, GC_gcj_kind);
	    if (0 == op) {
		UNLOCK();
		return(GC_oom_fn(lb));
	    }
#	    ifdef MERGE_SIZES
		lw = GC_size_map[lb];	/* May have been uninitialized.	*/
#	    endif
        } else {
            *opp = obj_link(op);
            GC_words_allocd += lw;
        }
	*(void **)op = ptr_to_struct_containing_descr;
	GC_ASSERT(((void **)op)[1] == 0);
	UNLOCK();
    } else {
	LOCK();
	maybe_finalize();
	op = (ptr_t)GENERAL_MALLOC((word)lb, GC_gcj_kind);
	if (0 == op) {
	    UNLOCK();
	    return(GC_oom_fn(lb));
	}
	*(void **)op = ptr_to_struct_containing_descr;
	UNLOCK();
    }
    return((GC_PTR) op);
}

/* Similar to GC_gcj_malloc, but add debug info.  This is allocated	*/
/* with GC_gcj_debug_kind.						*/
GC_PTR GC_debug_gcj_malloc(size_t lb, void * ptr_to_struct_containing_descr,
			   GC_EXTRA_PARAMS)
{
    GC_PTR result;

    /* We're careful to avoid extra calls, which could		 */
    /* confuse the backtrace.					*/
    LOCK();
    maybe_finalize();
    result = GC_generic_malloc_inner(lb + DEBUG_BYTES, GC_gcj_debug_kind);
    if (result == 0) {
	UNLOCK();
        GC_err_printf2("GC_debug_gcj_malloc(%ld, 0x%lx) returning NIL (",
        	       (unsigned long) lb,
		       (unsigned long) ptr_to_struct_containing_descr);
        GC_err_puts(s);
        GC_err_printf1(":%ld)\n", (unsigned long)i);
        return(GC_oom_fn(lb));
    }
    *((void **)((ptr_t)result + sizeof(oh))) = ptr_to_struct_containing_descr;
    UNLOCK();
    if (!GC_debugging_started) {
    	GC_start_debugging();
    }
    ADD_CALL_CHAIN(result, ra);
    return (GC_store_debug_info(result, (word)lb, s, (word)i));
}

/* Similar to GC_gcj_malloc, but the size is in words, and we don't	*/
/* adjust it.  The size is assumed to be such that it can be 	*/
/* allocated as a small object.					*/
void * GC_gcj_fast_malloc(size_t lw, void * ptr_to_struct_containing_descr)
{
ptr_t op;
ptr_t * opp;
DCL_LOCK_STATE;

    opp = &(GC_gcjobjfreelist[lw]);
    LOCK();
    op = *opp;
    if( EXPECT(op == 0, 0) ) {
	maybe_finalize();
        op = (ptr_t)GC_clear_stack(
		GC_generic_malloc_words_small_inner(lw, GC_gcj_kind));
	if (0 == op) {
	    UNLOCK();
	    return GC_oom_fn(WORDS_TO_BYTES(lw));
	}
    } else {
        *opp = obj_link(op);
        GC_words_allocd += lw;
    }
    *(void **)op = ptr_to_struct_containing_descr;
    UNLOCK();
    return((GC_PTR) op);
}

/* And a debugging version of the above:	*/
void * GC_debug_gcj_fast_malloc(size_t lw,
				void * ptr_to_struct_containing_descr,
				GC_EXTRA_PARAMS)
{
    GC_PTR result;
    size_t lb = WORDS_TO_BYTES(lw);

    /* We clone the code from GC_debug_gcj_malloc, so that we 	*/
    /* dont end up with extra frames on the stack, which could	*/
    /* confuse the backtrace.					*/
    LOCK();
    maybe_finalize();
    result = GC_generic_malloc_inner(lb + DEBUG_BYTES, GC_gcj_debug_kind);
    if (result == 0) {
	UNLOCK();
        GC_err_printf2("GC_debug_gcj_fast_malloc(%ld, 0x%lx) returning NIL (",
        	       (unsigned long) lw,
		       (unsigned long) ptr_to_struct_containing_descr);
        GC_err_puts(s);
        GC_err_printf1(":%ld)\n", (unsigned long)i);
        return GC_oom_fn(WORDS_TO_BYTES(lw));
    }
    *((void **)((ptr_t)result + sizeof(oh))) = ptr_to_struct_containing_descr;
    UNLOCK();
    if (!GC_debugging_started) {
    	GC_start_debugging();
    }
    ADD_CALL_CHAIN(result, ra);
    return (GC_store_debug_info(result, (word)lb, s, (word)i));
}

void * GC_gcj_malloc_ignore_off_page(size_t lb,
				     void * ptr_to_struct_containing_descr) 
{
register ptr_t op;
register ptr_t * opp;
register word lw;
DCL_LOCK_STATE;

    if( SMALL_OBJ(lb) ) {
#       ifdef MERGE_SIZES
	  lw = GC_size_map[lb];
#	else
	  lw = ALIGNED_WORDS(lb);
#       endif
	opp = &(GC_gcjobjfreelist[lw]);
	LOCK();
        if( (op = *opp) == 0 ) {
	    maybe_finalize();
            op = (ptr_t)GENERAL_MALLOC_IOP(lb, GC_gcj_kind);
#	    ifdef MERGE_SIZES
		lw = GC_size_map[lb];	/* May have been uninitialized.	*/
#	    endif
        } else {
            *opp = obj_link(op);
            GC_words_allocd += lw;
        }
	*(void **)op = ptr_to_struct_containing_descr;
	UNLOCK();
    } else {
	LOCK();
	maybe_finalize();
        op = (ptr_t)GENERAL_MALLOC_IOP(lb, GC_gcj_kind);
        if (0 != op) {
          *(void **)op = ptr_to_struct_containing_descr;
	}
        UNLOCK();
    }
    return((GC_PTR) op);
}

#else

char GC_no_gcj_support;

#endif  /* GC_GCJ_SUPPORT */