Makefile.in (JAVA_OBJS): Added boehm.o.

	* Makefile.in (JAVA_OBJS): Added boehm.o.
	(boehm.o): New target.
	* Make-lang.in (JAVA_SRCS): Added boehm.c.
	* java-tree.h (flag_use_boehm_gc): Declare.
	(get_boehm_type_descriptor): Declare.
	* lang.c (lang_f_options): Added `use-boehm-gc'.
	(flag_use_boehm_gc): New global.
	* lang-options.h: Added -fuse-boehm-gc.
	* boehm.c: New file.
	* class.c (get_dispatch_table): If class uses a Boehm type
	descriptor, put it in the vtable.
	(make_class_data): Removed dead code.

From-SVN: r32331

1 files changed, 152 insertions, 0 deletions

diff --git a/gcc/java/boehm.c b/gcc/java/boehm.c
new file mode 100644
index 0000000..370ff97
--- /dev/null
+++ b/gcc/java/boehm.c
@@ -0,0 +1,152 @@
+/* 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"
+
+/* 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.  */
+#define PROCEDURE_OBJECT_DESCRIPTOR integer_two_node
+
+/* 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 (unsigned HOST_WIDE_INT *low, unsigned HOST_WIDE_INT *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;
+}
+
+/* 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;
+  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)
+    return PROCEDURE_OBJECT_DESCRIPTOR;
+
+  bit = POINTER_SIZE;
+  /* 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;
+
+  field = TYPE_FIELDS (type);
+  if (DECL_NAME (field) == NULL_TREE)
+    field = TREE_CHAIN (field);  /* Skip dummy field for inherited data. */
+  for (count = 0; field != NULL_TREE; field = TREE_CHAIN (field))
+    {
+      if (FIELD_STATIC (field))
+	continue;
+
+      if (JREFERENCE_TYPE_P (TREE_TYPE (field)))
+	{
+	  last_set_index = count;
+	  /* First word in object corresponds to most significant byte
+	     of bitmap.  */
+	  set_bit (&low, &high, ubit - count);
+	  if (count > ubit - 2)
+	    pointer_after_end = 1;
+	}
+      else
+	all_bits_set = 0;
+
+      ++count;
+    }
+
+  /* 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)
+    {
+      /* 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;
+      ++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
+    value = PROCEDURE_OBJECT_DESCRIPTOR;
+
+  return value;
+}