264 lines
6.7 KiB
C
264 lines
6.7 KiB
C
/*
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* Copyright 1988, 1989 Hans-J. Boehm, Alan J. Demers
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* Copyright (c) 1991-1994 by Xerox Corporation. All rights reserved.
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* Copyright (c) 2000 by Hewlett-Packard Company. All rights reserved.
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*
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* THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED
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* OR IMPLIED. ANY USE IS AT YOUR OWN RISK.
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*
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* Permission is hereby granted to use or copy this program
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* for any purpose, provided the above notices are retained on all copies.
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* Permission to modify the code and to distribute modified code is granted,
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* provided the above notices are retained, and a notice that the code was
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* modified is included with the above copyright notice.
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*
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* This file contains the functions:
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* ptr_t GC_build_flXXX(h, old_fl)
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* void GC_new_hblk(n)
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*/
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/* Boehm, May 19, 1994 2:09 pm PDT */
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# include <stdio.h>
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# include "private/gc_priv.h"
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#ifndef SMALL_CONFIG
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/*
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* Build a free list for size 1 objects inside hblk h. Set the last link to
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* be ofl. Return a pointer tpo the first free list entry.
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*/
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ptr_t GC_build_fl1(h, ofl)
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struct hblk *h;
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ptr_t ofl;
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{
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register word * p = h -> hb_body;
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register word * lim = (word *)(h + 1);
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p[0] = (word)ofl;
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p[1] = (word)(p);
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p[2] = (word)(p+1);
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p[3] = (word)(p+2);
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p += 4;
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for (; p < lim; p += 4) {
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p[0] = (word)(p-1);
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p[1] = (word)(p);
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p[2] = (word)(p+1);
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p[3] = (word)(p+2);
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};
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return((ptr_t)(p-1));
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}
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/* The same for size 2 cleared objects */
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ptr_t GC_build_fl_clear2(h, ofl)
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struct hblk *h;
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ptr_t ofl;
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{
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register word * p = h -> hb_body;
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register word * lim = (word *)(h + 1);
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p[0] = (word)ofl;
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p[1] = 0;
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p[2] = (word)p;
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p[3] = 0;
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p += 4;
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for (; p < lim; p += 4) {
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p[0] = (word)(p-2);
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p[1] = 0;
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p[2] = (word)p;
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p[3] = 0;
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};
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return((ptr_t)(p-2));
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}
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/* The same for size 3 cleared objects */
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ptr_t GC_build_fl_clear3(h, ofl)
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struct hblk *h;
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ptr_t ofl;
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{
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register word * p = h -> hb_body;
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register word * lim = (word *)(h + 1) - 2;
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p[0] = (word)ofl;
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p[1] = 0;
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p[2] = 0;
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p += 3;
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for (; p < lim; p += 3) {
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p[0] = (word)(p-3);
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p[1] = 0;
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p[2] = 0;
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};
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return((ptr_t)(p-3));
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}
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/* The same for size 4 cleared objects */
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ptr_t GC_build_fl_clear4(h, ofl)
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struct hblk *h;
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ptr_t ofl;
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{
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register word * p = h -> hb_body;
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register word * lim = (word *)(h + 1);
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p[0] = (word)ofl;
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p[1] = 0;
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p[2] = 0;
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p[3] = 0;
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p += 4;
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for (; p < lim; p += 4) {
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PREFETCH_FOR_WRITE(p+64);
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p[0] = (word)(p-4);
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p[1] = 0;
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CLEAR_DOUBLE(p+2);
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};
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return((ptr_t)(p-4));
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}
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/* The same for size 2 uncleared objects */
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ptr_t GC_build_fl2(h, ofl)
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struct hblk *h;
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ptr_t ofl;
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{
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register word * p = h -> hb_body;
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register word * lim = (word *)(h + 1);
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p[0] = (word)ofl;
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p[2] = (word)p;
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p += 4;
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for (; p < lim; p += 4) {
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p[0] = (word)(p-2);
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p[2] = (word)p;
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};
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return((ptr_t)(p-2));
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}
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/* The same for size 4 uncleared objects */
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ptr_t GC_build_fl4(h, ofl)
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struct hblk *h;
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ptr_t ofl;
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{
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register word * p = h -> hb_body;
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register word * lim = (word *)(h + 1);
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p[0] = (word)ofl;
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p[4] = (word)p;
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p += 8;
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for (; p < lim; p += 8) {
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PREFETCH_FOR_WRITE(p+64);
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p[0] = (word)(p-4);
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p[4] = (word)p;
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};
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return((ptr_t)(p-4));
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}
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#endif /* !SMALL_CONFIG */
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/* Build a free list for objects of size sz inside heap block h. */
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/* Clear objects inside h if clear is set. Add list to the end of */
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/* the free list we build. Return the new free list. */
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/* This could be called without the main GC lock, if we ensure that */
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/* there is no concurrent collection which might reclaim objects that */
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/* we have not yet allocated. */
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ptr_t GC_build_fl(h, sz, clear, list)
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struct hblk *h;
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word sz;
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GC_bool clear;
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ptr_t list;
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{
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word *p, *prev;
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word *last_object; /* points to last object in new hblk */
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/* Do a few prefetches here, just because its cheap. */
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/* If we were more serious about it, these should go inside */
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/* the loops. But write prefetches usually don't seem to */
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/* matter much. */
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PREFETCH_FOR_WRITE((char *)h);
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PREFETCH_FOR_WRITE((char *)h + 128);
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PREFETCH_FOR_WRITE((char *)h + 256);
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PREFETCH_FOR_WRITE((char *)h + 378);
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/* Handle small objects sizes more efficiently. For larger objects */
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/* the difference is less significant. */
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# ifndef SMALL_CONFIG
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switch (sz) {
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case 1: return GC_build_fl1(h, list);
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case 2: if (clear) {
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return GC_build_fl_clear2(h, list);
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} else {
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return GC_build_fl2(h, list);
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}
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case 3: if (clear) {
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return GC_build_fl_clear3(h, list);
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} else {
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/* It's messy to do better than the default here. */
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break;
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}
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case 4: if (clear) {
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return GC_build_fl_clear4(h, list);
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} else {
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return GC_build_fl4(h, list);
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}
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default:
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break;
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}
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# endif /* !SMALL_CONFIG */
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/* Clear the page if necessary. */
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if (clear) BZERO(h, HBLKSIZE);
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/* Add objects to free list */
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p = &(h -> hb_body[sz]); /* second object in *h */
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prev = &(h -> hb_body[0]); /* One object behind p */
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last_object = (word *)((char *)h + HBLKSIZE);
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last_object -= sz;
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/* Last place for last object to start */
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/* make a list of all objects in *h with head as last object */
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while (p <= last_object) {
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/* current object's link points to last object */
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obj_link(p) = (ptr_t)prev;
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prev = p;
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p += sz;
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}
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p -= sz; /* p now points to last object */
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/*
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* put p (which is now head of list of objects in *h) as first
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* pointer in the appropriate free list for this size.
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*/
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obj_link(h -> hb_body) = list;
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return ((ptr_t)p);
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}
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/*
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* Allocate a new heapblock for small objects of size n.
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* Add all of the heapblock's objects to the free list for objects
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* of that size.
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* Set all mark bits if objects are uncollectable.
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* Will fail to do anything if we are out of memory.
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*/
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void GC_new_hblk(sz, kind)
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register word sz;
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int kind;
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{
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register struct hblk *h; /* the new heap block */
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register GC_bool clear = GC_obj_kinds[kind].ok_init;
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# ifdef PRINTSTATS
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if ((sizeof (struct hblk)) > HBLKSIZE) {
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ABORT("HBLK SZ inconsistency");
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}
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# endif
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if (GC_debugging_started) clear = TRUE;
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/* Allocate a new heap block */
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h = GC_allochblk(sz, kind, 0);
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if (h == 0) return;
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/* Mark all objects if appropriate. */
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if (IS_UNCOLLECTABLE(kind)) GC_set_hdr_marks(HDR(h));
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/* Build the free list */
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GC_obj_kinds[kind].ok_freelist[sz] =
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GC_build_fl(h, sz, clear, GC_obj_kinds[kind].ok_freelist[sz]);
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}
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