misc.c

linux下建立JAVA虚拟机的源码KAFFE

/* 
 * Copyright 1988, 1989 Hans-J. Boehm, Alan J. Demers
 * Copyright (c) 1991-1994 by Xerox Corporation.  All rights reserved.
 * Copyright (c) 1999-2001 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 */


#include <stdio.h>
#include <limits.h>
#ifndef _WIN32_WCE
#include <signal.h>
#endif

#define I_HIDE_POINTERS	/* To make GC_call_with_alloc_lock visible */
#include "private/gc_pmark.h"

#ifdef GC_SOLARIS_THREADS
# include <sys/syscall.h>
#endif
#if defined(MSWIN32) || defined(MSWINCE)
# define WIN32_LEAN_AND_MEAN
# define NOSERVICE
# include <windows.h>
# include <tchar.h>
#endif

# ifdef THREADS
#   ifdef PCR
#     include "il/PCR_IL.h"
      PCR_Th_ML GC_allocate_ml;
#   else
#     ifdef SRC_M3
	/* Critical section counter is defined in the M3 runtime 	*/
	/* That's all we use.						*/
#     else
#	ifdef GC_SOLARIS_THREADS
	  mutex_t GC_allocate_ml;	/* Implicitly initialized.	*/
#	else
#          if defined(GC_WIN32_THREADS) 
#             if defined(GC_PTHREADS)
		  pthread_mutex_t GC_allocate_ml = PTHREAD_MUTEX_INITIALIZER;
#	      elif defined(GC_DLL)
		 __declspec(dllexport) CRITICAL_SECTION GC_allocate_ml;
#	      else
		 CRITICAL_SECTION GC_allocate_ml;
#	      endif
#          else
#             if defined(GC_PTHREADS) && !defined(GC_SOLARIS_THREADS)
#		if defined(USE_SPIN_LOCK)
	          pthread_t GC_lock_holder = NO_THREAD;
#	        else
		  pthread_mutex_t GC_allocate_ml = PTHREAD_MUTEX_INITIALIZER;
	          pthread_t GC_lock_holder = NO_THREAD;
			/* Used only for assertions, and to prevent	 */
			/* recursive reentry in the system call wrapper. */
#		endif 
#    	      else
	          --> declare allocator lock here
#	      endif
#	   endif
#	endif
#     endif
#   endif
# endif

#if defined(NOSYS) || defined(ECOS)
#undef STACKBASE
#endif

/* Dont unnecessarily call GC_register_main_static_data() in case 	*/
/* dyn_load.c isn't linked in.						*/
#ifdef DYNAMIC_LOADING
# define GC_REGISTER_MAIN_STATIC_DATA() GC_register_main_static_data()
#else
# define GC_REGISTER_MAIN_STATIC_DATA() TRUE
#endif

GC_FAR struct _GC_arrays GC_arrays /* = { 0 } */;


GC_bool GC_debugging_started = FALSE;
	/* defined here so we don't have to load debug_malloc.o */

void (*GC_check_heap) GC_PROTO((void)) = (void (*) GC_PROTO((void)))0;
void (*GC_print_all_smashed) GC_PROTO((void)) = (void (*) GC_PROTO((void)))0;

void (*GC_start_call_back) GC_PROTO((void)) = (void (*) GC_PROTO((void)))0;

ptr_t GC_stackbottom = 0;

#ifdef IA64
  ptr_t GC_register_stackbottom = 0;
#endif

GC_bool GC_dont_gc = 0;

GC_bool GC_dont_precollect = 0;

GC_bool GC_quiet = 0;

GC_bool GC_print_stats = 0;

GC_bool GC_print_back_height = 0;

#ifndef NO_DEBUGGING
  GC_bool GC_dump_regularly = 0;  /* Generate regular debugging dumps. */
#endif

#ifdef KEEP_BACK_PTRS
  long GC_backtraces = 0;	/* Number of random backtraces to 	*/
  				/* generate for each GC.		*/
#endif

#ifdef FIND_LEAK
  int GC_find_leak = 1;
#else
  int GC_find_leak = 0;
#endif

#ifdef ALL_INTERIOR_POINTERS
  int GC_all_interior_pointers = 1;
#else
  int GC_all_interior_pointers = 0;
#endif

long GC_large_alloc_warn_interval = 5;
	/* Interval between unsuppressed warnings.	*/

long GC_large_alloc_warn_suppressed = 0;
	/* Number of warnings suppressed so far.	*/

/*ARGSUSED*/
GC_PTR GC_default_oom_fn GC_PROTO((size_t bytes_requested))
{
    return(0);
}

GC_PTR (*GC_oom_fn) GC_PROTO((size_t bytes_requested)) = GC_default_oom_fn;

extern signed_word GC_mem_found;

void * GC_project2(arg1, arg2)
void *arg1;
void *arg2;
{
  return arg2;
}

# ifdef MERGE_SIZES
    /* Set things up so that GC_size_map[i] >= words(i),		*/
    /* but not too much bigger						*/
    /* and so that size_map contains relatively few distinct entries 	*/
    /* This is stolen from Russ Atkinson's Cedar quantization		*/
    /* alogrithm (but we precompute it).				*/


    void GC_init_size_map()
    {
	register unsigned i;

	/* Map size 0 to something bigger.			*/
	/* This avoids problems at lower levels.		*/
	/* One word objects don't have to be 2 word aligned,	*/
	/* unless we're using mark bytes.	   		*/
	  for (i = 0; i < sizeof(word); i++) {
	      GC_size_map[i] = MIN_WORDS;
	  }
#	  if MIN_WORDS > 1
	    GC_size_map[sizeof(word)] = MIN_WORDS;
#	  else
	    GC_size_map[sizeof(word)] = ROUNDED_UP_WORDS(sizeof(word));
#	  endif
	for (i = sizeof(word) + 1; i <= 8 * sizeof(word); i++) {
	    GC_size_map[i] = ALIGNED_WORDS(i);
	}
	for (i = 8*sizeof(word) + 1; i <= 16 * sizeof(word); i++) {
	      GC_size_map[i] = (ROUNDED_UP_WORDS(i) + 1) & (~1);
	}
#	ifdef GC_GCJ_SUPPORT
	   /* Make all sizes up to 32 words predictable, so that a 	*/
	   /* compiler can statically perform the same computation,	*/
	   /* or at least a computation that results in similar size	*/
	   /* classes.							*/
	   for (i = 16*sizeof(word) + 1; i <= 32 * sizeof(word); i++) {
	      GC_size_map[i] = (ROUNDED_UP_WORDS(i) + 3) & (~3);
	   }
#	endif
	/* We leave the rest of the array to be filled in on demand. */
    }
    
    /* Fill in additional entries in GC_size_map, including the ith one */
    /* We assume the ith entry is currently 0.				*/
    /* Note that a filled in section of the array ending at n always    */
    /* has length at least n/4.						*/
    void GC_extend_size_map(i)
    word i;
    {
        word orig_word_sz = ROUNDED_UP_WORDS(i);
        word word_sz = orig_word_sz;
    	register word byte_sz = WORDS_TO_BYTES(word_sz);
    				/* The size we try to preserve.		*/
    				/* Close to to i, unless this would	*/
    				/* introduce too many distinct sizes.	*/
    	word smaller_than_i = byte_sz - (byte_sz >> 3);
    	word much_smaller_than_i = byte_sz - (byte_sz >> 2);
    	register word low_limit;	/* The lowest indexed entry we 	*/
    					/* initialize.			*/
    	register word j;
    	
    	if (GC_size_map[smaller_than_i] == 0) {
    	    low_limit = much_smaller_than_i;
    	    while (GC_size_map[low_limit] != 0) low_limit++;
    	} else {
    	    low_limit = smaller_than_i + 1;
    	    while (GC_size_map[low_limit] != 0) low_limit++;
    	    word_sz = ROUNDED_UP_WORDS(low_limit);
    	    word_sz += word_sz >> 3;
    	    if (word_sz < orig_word_sz) word_sz = orig_word_sz;
    	}
#	ifdef ALIGN_DOUBLE
	    word_sz += 1;
	    word_sz &= ~1;
#	endif
	if (word_sz > MAXOBJSZ) {
	    word_sz = MAXOBJSZ;
	}
	/* If we can fit the same number of larger objects in a block,	*/
	/* do so.							*/ 
	{
	    size_t number_of_objs = BODY_SZ/word_sz;
	    word_sz = BODY_SZ/number_of_objs;
#	    ifdef ALIGN_DOUBLE
		word_sz &= ~1;
#	    endif
	}
    	byte_sz = WORDS_TO_BYTES(word_sz);
	if (GC_all_interior_pointers) {
	    /* We need one extra byte; don't fill in GC_size_map[byte_sz] */
	    byte_sz -= EXTRA_BYTES;
	}

    	for (j = low_limit; j <= byte_sz; j++) GC_size_map[j] = word_sz;  
    }
# endif


/*
 * The following is a gross hack to deal with a problem that can occur
 * on machines that are sloppy about stack frame sizes, notably SPARC.
 * Bogus pointers may be written to the stack and not cleared for
 * a LONG time, because they always fall into holes in stack frames
 * that are not written.  We partially address this by clearing
 * sections of the stack whenever we get control.
 */
word GC_stack_last_cleared = 0;	/* GC_no when we last did this */
# ifdef THREADS
#   define BIG_CLEAR_SIZE 2048	/* Clear this much now and then.	*/
#   define SMALL_CLEAR_SIZE 256 /* Clear this much every time.		*/
# endif
# define CLEAR_SIZE 213  /* Granularity for GC_clear_stack_inner */
# define DEGRADE_RATE 50

word GC_min_sp;		/* Coolest stack pointer value from which we've */
			/* already cleared the stack.			*/
			
word GC_high_water;
			/* "hottest" stack pointer value we have seen	*/
			/* recently.  Degrades over time.		*/

word GC_words_allocd_at_reset;

#if defined(ASM_CLEAR_CODE)
  extern ptr_t GC_clear_stack_inner();
#else  
/* Clear the stack up to about limit.  Return arg. */
/*ARGSUSED*/
ptr_t GC_clear_stack_inner(arg, limit)
ptr_t arg;
word limit;
{
    word dummy[CLEAR_SIZE];
    
    BZERO(dummy, CLEAR_SIZE*sizeof(word));
    if ((word)(dummy) COOLER_THAN limit) {
        (void) GC_clear_stack_inner(arg, limit);
    }
    /* Make sure the recursive call is not a tail call, and the bzero	*/
    /* call is not recognized as dead code.				*/
    GC_noop1((word)dummy);
    return(arg);
}
#endif

/* Clear some of the inaccessible part of the stack.  Returns its	*/
/* argument, so it can be used in a tail call position, hence clearing  */
/* another frame.							*/
ptr_t GC_clear_stack(arg)
ptr_t arg;
{
    register word sp = (word)GC_approx_sp();  /* Hotter than actual sp */
#   ifdef THREADS
        word dummy[SMALL_CLEAR_SIZE];
	static unsigned random_no = 0;
       			 	 /* Should be more random than it is ... */
				 /* Used to occasionally clear a bigger	 */
				 /* chunk.				 */
#   endif
    register word limit;
    
#   define SLOP 400
	/* Extra bytes we clear every time.  This clears our own	*/
	/* activation record, and should cause more frequent		*/
	/* clearing near the cold end of the stack, a good thing.	*/
#   define GC_SLOP 4000
	/* We make GC_high_water this much hotter than we really saw   	*/
	/* saw it, to cover for GC noise etc. above our current frame.	*/
#   define CLEAR_THRESHOLD 100000
	/* We restart the clearing process after this many bytes of	*/
	/* allocation.  Otherwise very heavily recursive programs	*/
	/* with sparse stacks may result in heaps that grow almost	*/
	/* without bounds.  As the heap gets larger, collection 	*/
	/* frequency decreases, thus clearing frequency would decrease, */
	/* thus more junk remains accessible, thus the heap gets	*/
	/* larger ...							*/
# ifdef THREADS
    if (++random_no % 13 == 0) {
	limit = sp;
	MAKE_HOTTER(limit, BIG_CLEAR_SIZE*sizeof(word));
        limit &= ~0xf;	/* Make it sufficiently aligned for assembly	*/
        		/* implementations of GC_clear_stack_inner.	*/
	return GC_clear_stack_inner(arg, limit);
    } else {
	BZERO(dummy, SMALL_CLEAR_SIZE*sizeof(word));
	return arg;
    }
# else
    if (GC_gc_no > GC_stack_last_cleared) {
        /* Start things over, so we clear the entire stack again */
        if (GC_stack_last_cleared == 0) GC_high_water = (word) GC_stackbottom;
        GC_min_sp = GC_high_water;
        GC_stack_last_cleared = GC_gc_no;
        GC_words_allocd_at_reset = GC_words_allocd;
    }
    /* Adjust GC_high_water */
        MAKE_COOLER(GC_high_water, WORDS_TO_BYTES(DEGRADE_RATE) + GC_SLOP);
        if (sp HOTTER_THAN GC_high_water) {
            GC_high_water = sp;
        }
        MAKE_HOTTER(GC_high_water, GC_SLOP);
    limit = GC_min_sp;
    MAKE_HOTTER(limit, SLOP);
    if (sp COOLER_THAN limit) {
        limit &= ~0xf;	/* Make it sufficiently aligned for assembly	*/
        		/* implementations of GC_clear_stack_inner.	*/
        GC_min_sp = sp;
        return(GC_clear_stack_inner(arg, limit));
    } else if (WORDS_TO_BYTES(GC_words_allocd - GC_words_allocd_at_reset)
    	       > CLEAR_THRESHOLD) {
    	/* Restart clearing process, but limit how much clearing we do. */
    	GC_min_sp = sp;
    	MAKE_HOTTER(GC_min_sp, CLEAR_THRESHOLD/4);
    	if (GC_min_sp HOTTER_THAN GC_high_water) GC_min_sp = GC_high_water;
    	GC_words_allocd_at_reset = GC_words_allocd;
    }  
    return(arg);
# endif
}


/* Return a pointer to the base address of p, given a pointer to a	*/
/* an address within an object.  Return 0 o.w.				*/
# ifdef __STDC__
    GC_PTR GC_base(GC_PTR p)
# else
    GC_PTR GC_base(p)
    GC_PTR p;
# endif
{
    register word r;
    register struct hblk *h;
    register bottom_index *bi;
    register hdr *candidate_hdr;
    register word limit;