+++ /dev/null
-/* Functions related to the Boehm garbage collector.
- Copyright (C) 2000 Free Software Foundation, Inc.
-
-This file is part of GNU CC.
-
-GNU CC is free software; you can redistribute it and/or modify
-it under the terms of the GNU General Public License as published by
-the Free Software Foundation; either version 2, or (at your option)
-any later version.
-
-GNU CC is distributed in the hope that it will be useful,
-but WITHOUT ANY WARRANTY; without even the implied warranty of
-MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-GNU General Public License for more details.
-
-You should have received a copy of the GNU General Public License
-along with GNU CC; see the file COPYING. If not, write to
-the Free Software Foundation, 59 Temple Place - Suite 330,
-Boston, MA 02111-1307, USA.
-
-Java and all Java-based marks are trademarks or registered trademarks
-of Sun Microsystems, Inc. in the United States and other countries.
-The Free Software Foundation is independent of Sun Microsystems, Inc. */
-
-/* Written by Tom Tromey <tromey@cygnus.com>. */
-
-#include <config.h>
-
-#include "system.h"
-#include "tree.h"
-#include "java-tree.h"
-#include "parse.h"
-#include "toplev.h"
-
-static void mark_reference_fields PARAMS ((tree,
- unsigned HOST_WIDE_INT *,
- unsigned HOST_WIDE_INT *,
- unsigned int,
- int *, int *,
- int *,
- HOST_WIDE_INT *));
-static void set_bit PARAMS ((unsigned HOST_WIDE_INT *,
- unsigned HOST_WIDE_INT *,
- unsigned int));
-
-/* Treat two HOST_WIDE_INT's as a contiguous bitmap, with bit 0 being
- the least significant. This function sets bit N in the bitmap. */
-static void
-set_bit (low, high, n)
- unsigned HOST_WIDE_INT *low, *high;
- unsigned int n;
-{
- HOST_WIDE_INT *which;
-
- if (n >= HOST_BITS_PER_WIDE_INT)
- {
- n -= HOST_BITS_PER_WIDE_INT;
- which = high;
- }
- else
- which = low;
-
- *which |= (HOST_WIDE_INT) 1 << n;
-}
-
-/* Recursively mark reference fields. */
-static void
-mark_reference_fields (field, low, high, ubit,
- pointer_after_end, all_bits_set,
- last_set_index, last_view_index)
- tree field;
- unsigned HOST_WIDE_INT *low, *high;
- unsigned int ubit;
- int *pointer_after_end, *all_bits_set;
- int *last_set_index;
- HOST_WIDE_INT *last_view_index;
-{
- /* See if we have fields from our superclass. */
- if (DECL_NAME (field) == NULL_TREE)
- {
- mark_reference_fields (TYPE_FIELDS (TREE_TYPE (field)),
- low, high, ubit,
- pointer_after_end, all_bits_set,
- last_set_index, last_view_index);
- field = TREE_CHAIN (field);
- }
-
- for (; field != NULL_TREE; field = TREE_CHAIN (field))
- {
- HOST_WIDE_INT offset;
- HOST_WIDE_INT size_bytes;
-
- if (FIELD_STATIC (field))
- continue;
-
- offset = int_byte_position (field);
- size_bytes = int_size_in_bytes (TREE_TYPE (field));
- if (JREFERENCE_TYPE_P (TREE_TYPE (field))
- /* An `object' of type gnu.gcj.RawData is actually non-Java
- data. */
- && TREE_TYPE (field) != rawdata_ptr_type_node)
- {
- unsigned int count;
- unsigned int size_words;
- unsigned int i;
-
- /* If this reference slot appears to overlay a slot we think
- we already covered, then we are doomed. */
- if (offset <= *last_view_index)
- abort ();
-
- count = offset * BITS_PER_UNIT / POINTER_SIZE;
- size_words = size_bytes * BITS_PER_UNIT / POINTER_SIZE;
-
- *last_set_index = count;
-
- /* First word in object corresponds to most significant byte of
- bitmap.
-
- In the case of a multiple-word record, we set pointer
- bits for all words in the record. This is conservative, but the
- size_words != 1 case is impossible in regular java code. */
- for (i = 0; i < size_words; ++i)
- set_bit (low, high, ubit - count - i - 1);
-
- if (count >= ubit - 2)
- *pointer_after_end = 1;
-
- /* If we saw a non-reference field earlier, then we can't
- use the count representation. We keep track of that in
- *ALL_BITS_SET. */
- if (! *all_bits_set)
- *all_bits_set = -1;
- }
- else if (*all_bits_set > 0)
- *all_bits_set = 0;
-
- *last_view_index = offset;
- }
-}
-
-/* Return the marking bitmap for the class TYPE. For now this is a
- single word describing the type. */
-tree
-get_boehm_type_descriptor (tree type)
-{
- unsigned int count, log2_size, ubit;
- int bit;
- int all_bits_set = 1;
- int last_set_index = 0;
- HOST_WIDE_INT last_view_index = -1;
- int pointer_after_end = 0;
- unsigned HOST_WIDE_INT low = 0, high = 0;
- tree field, value;
-
- /* If the GC wasn't requested, just use a null pointer. */
- if (! flag_use_boehm_gc)
- return null_pointer_node;
-
- /* If we have a type of unknown size, use a proc. */
- if (int_size_in_bytes (type) == -1)
- goto procedure_object_descriptor;
-
- bit = POINTER_SIZE / BITS_PER_UNIT;
- /* The size of this node has to be known. And, we only support 32
- and 64 bit targets, so we need to know that the log2 is one of
- our values. */
- log2_size = exact_log2 (bit);
- if (bit == -1 || (log2_size != 2 && log2_size != 3))
- {
- /* This means the GC isn't supported. We should probably
- abort or give an error. Instead, for now, we just silently
- revert. FIXME. */
- return null_pointer_node;
- }
- bit *= BITS_PER_UNIT;
-
- /* Warning avoidance. */
- ubit = (unsigned int) bit;
-
- if (type == class_type_node)
- goto procedure_object_descriptor;
-
- field = TYPE_FIELDS (type);
- mark_reference_fields (field, &low, &high, ubit,
- &pointer_after_end, &all_bits_set,
- &last_set_index, &last_view_index);
-
- /* If the object is all pointers, or if the part with pointers fits
- in our bitmap, then we are ok. Otherwise we have to allocate it
- a different way. */
- if (all_bits_set != -1)
- {
- /* In this case the initial part of the object is all reference
- fields, and the end of the object is all non-reference
- fields. We represent the mark as a count of the fields,
- shifted. In the GC the computation looks something like
- this:
- value = DS_LENGTH | WORDS_TO_BYTES (last_set_index + 1);
- DS_LENGTH is 0.
- WORDS_TO_BYTES shifts by log2(bytes-per-pointer). */
- count = 0;
- low = 0;
- high = 0;
- ++last_set_index;
- while (last_set_index)
- {
- if ((last_set_index & 1))
- set_bit (&low, &high, log2_size + count);
- last_set_index >>= 1;
- ++count;
- }
- value = build_int_2 (low, high);
- }
- else if (! pointer_after_end)
- {
- /* Bottom two bits for bitmap mark type are 01. */
- set_bit (&low, &high, 0);
- value = build_int_2 (low, high);
- }
- else
- {
- /* Compute a procedure-based object descriptor. We know that our
- `kind' is 0, and `env' is likewise 0, so we have a simple
- computation. From the GC sources:
- (((((env) << LOG_MAX_MARK_PROCS) | (proc_index)) << DS_TAG_BITS) \
- | DS_PROC)
- Here DS_PROC == 2. */
- procedure_object_descriptor:
- value = build_int_2 (2, 0);
- }
-
- TREE_TYPE (value) = type_for_mode (ptr_mode, 1);
- return value;
-}
projects / msp430-gcc.git / blobdiff