/* Simple garbage collection for the GNU compiler.
   Copyright (C) 1999 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.  */

/* Generic garbage collection (GC) functions and data, not specific to
   any particular GC implementation.  */

#include "config.h"
#include "system.h"
#include "rtl.h"
#include "tree.h"
#include "tm_p.h"
#include "hash.h"
#include "varray.h"
#include "ggc.h"

static void ggc_mark_rtx_ptr PARAMS ((void *));
static void ggc_mark_tree_ptr PARAMS ((void *));
static void ggc_mark_tree_varray_ptr PARAMS ((void *));
static void ggc_mark_tree_hash_table_ptr PARAMS ((void *));
static void ggc_mark_string_ptr PARAMS ((void *));
static boolean ggc_mark_tree_hash_table_entry PARAMS ((struct hash_entry *,
						       hash_table_key));

/* Maintain global roots that are preserved during GC.  */

/* Global roots that are preserved during calls to gc.  */

struct ggc_root
{
  struct ggc_root *next;
  void *base;
  int nelt;
  int size;
  void (*cb) PROTO ((void *));
};

static struct ggc_root *roots;

/* Type-correct function to pass to ggc_add_root.  It just forwards
   *ELT (which is an rtx) to ggc_mark_tree_varray.  */

static void
ggc_mark_rtx_ptr (elt)
     void *elt;
{
  ggc_mark_rtx (*(rtx *)elt);
}

/* Type-correct function to pass to ggc_add_root.  It just forwards
   *ELT (which is a tree) to ggc_mark_tree.  */

static void
ggc_mark_tree_ptr (elt)
     void *elt;
{
  ggc_mark_tree (*(tree *)elt);
}

/* Type-correct function to pass to ggc_add_root.  It just forwards
   ELT (which is really a varray_type *) to ggc_mark_tree_varray.  */

static void
ggc_mark_tree_varray_ptr (elt)
     void *elt;
{
  ggc_mark_tree_varray (*(varray_type *)elt);
}

/* Type-correct function to pass to ggc_add_root.  It just forwards
   ELT (which is really a struct hash_table **) to
   ggc_mark_tree_hash_table.  */

static void
ggc_mark_tree_hash_table_ptr (elt)
     void *elt;
{
  ggc_mark_tree_hash_table (*(struct hash_table **) elt);
}

static void
ggc_mark_string_ptr (elt)
     void *elt;
{
  ggc_mark_string (*(char **)elt);
}

void
ggc_add_root (base, nelt, size, cb)
     void *base;
     int nelt, size;
     void (*cb) PROTO ((void *));
{
  struct ggc_root *x = (struct ggc_root *) xmalloc (sizeof (*x));

  x->next = roots;
  x->base = base;
  x->nelt = nelt;
  x->size = size;
  x->cb = cb;

  roots = x;
}

void
ggc_add_rtx_root (base, nelt)
     rtx *base;
     int nelt;
{
  ggc_add_root (base, nelt, sizeof(rtx), ggc_mark_rtx_ptr);
}

void
ggc_add_tree_root (base, nelt)
     tree *base;
     int nelt;
{
  ggc_add_root (base, nelt, sizeof(tree), ggc_mark_tree_ptr);
}

/* Add V (a varray full of trees) to the list of GC roots.  */

void
ggc_add_tree_varray_root (base, nelt)
     varray_type *base;
     int nelt;
{
  ggc_add_root (base, nelt, sizeof (varray_type), 
		ggc_mark_tree_varray_ptr);
}

/* Add HT (a hash-table where ever key is a tree) to the list of GC
   roots.  */

void
ggc_add_tree_hash_table_root (base, nelt)
     struct hash_table **base;
     int nelt;
{
  ggc_add_root (base, nelt, sizeof (struct hash_table *), 
		ggc_mark_tree_hash_table_ptr);
}

void
ggc_add_string_root (base, nelt)
     char **base;
     int nelt;
{
  ggc_add_root (base, nelt, sizeof (char *), ggc_mark_string_ptr);
}


void
ggc_del_root (base)
     void *base;
{
  struct ggc_root *x, **p;

  p = &roots, x = roots;
  while (x)
    {
      if (x->base == base)
	{
	  *p = x->next;
	  free (x);
	  return;
	}
      p = &x->next;
      x = x->next;
    }

  abort();
}

void
ggc_mark_roots ()
{
  struct ggc_root* x;
  
  for (x = roots; x != NULL; x = x->next)
    {
      char *elt = x->base;
      int s = x->size, n = x->nelt;
      void (*cb) PROTO ((void *)) = x->cb;
      int i;

      for (i = 0; i < n; ++i, elt += s)
	(*cb)(elt);
    }
}

void
ggc_mark_rtx_children (r)
     rtx r;
{
  const char *fmt;
  int i;

  /* ??? If (some of) these are really pass-dependant info, do we have
     any right poking our noses in?  */
  switch (GET_CODE (r))
    {
    case JUMP_INSN:
      ggc_mark_rtx (JUMP_LABEL (r));
      break;
    case CODE_LABEL:
      ggc_mark_rtx (LABEL_REFS (r));
      break;
    case LABEL_REF:
      ggc_mark_rtx (LABEL_NEXTREF (r));
      ggc_mark_rtx (CONTAINING_INSN (r));
      break;
    case ADDRESSOF:
      ggc_mark_tree (ADDRESSOF_DECL (r));
      break;
    case CONST_DOUBLE:
      ggc_mark_rtx (CONST_DOUBLE_CHAIN (r));
      break;
    case NOTE:
      switch (NOTE_LINE_NUMBER (r))
	{
	case NOTE_INSN_RANGE_START:
	case NOTE_INSN_RANGE_END:
	case NOTE_INSN_LIVE:
	  ggc_mark_rtx (NOTE_RANGE_INFO (r));
	  break;

	case NOTE_INSN_BLOCK_BEG:
	case NOTE_INSN_BLOCK_END:
	  ggc_mark_tree (NOTE_BLOCK (r));
	  break;

	default:
	  if (NOTE_LINE_NUMBER (r) >= 0)
	    ggc_mark_string (NOTE_SOURCE_FILE (r));
	  break;
	}
      break;

    default:
      break;
    }

  for (fmt = GET_RTX_FORMAT (GET_CODE (r)), i = 0; *fmt ; ++fmt, ++i)
    {
      switch (*fmt)
	{
	case 'e': case 'u':
	  ggc_mark_rtx (XEXP (r, i));
	  break;
	case 'V': case 'E':
	  ggc_mark_rtvec (XVEC (r, i));
	  break;
	case 'S': case 's':
	  ggc_mark_if_gcable (XSTR (r, i));
	  break;
	}
    }
}

void
ggc_mark_rtvec_children (v)
     rtvec v;
{
  int i;

  i = GET_NUM_ELEM (v);
  while (--i >= 0)
    ggc_mark_rtx (RTVEC_ELT (v, i));
}

void
ggc_mark_tree_children (t)
     tree t;
{
  /* Bits from common.  */
  ggc_mark_tree (TREE_TYPE (t));
  ggc_mark_tree (TREE_CHAIN (t));

  /* Some nodes require special handling.  */
  switch (TREE_CODE (t))
    {
    case TREE_LIST:
      ggc_mark_tree (TREE_PURPOSE (t));
      ggc_mark_tree (TREE_VALUE (t));
      return;

    case TREE_VEC:
      {
	int i = TREE_VEC_LENGTH (t);
	while (--i >= 0)
	  ggc_mark_tree (TREE_VEC_ELT (t, i));
	return;
      }

    case SAVE_EXPR:
      ggc_mark_tree (TREE_OPERAND (t, 0));
      ggc_mark_tree (SAVE_EXPR_CONTEXT (t));
      ggc_mark_rtx (SAVE_EXPR_RTL (t));
      return;

    case RTL_EXPR:
      ggc_mark_rtx (RTL_EXPR_SEQUENCE (t));
      ggc_mark_rtx (RTL_EXPR_RTL (t));
      return;

    case CALL_EXPR:
      ggc_mark_tree (TREE_OPERAND (t, 0));
      ggc_mark_tree (TREE_OPERAND (t, 1));
      ggc_mark_rtx (CALL_EXPR_RTL (t));
      return;

    case COMPLEX_CST:
      ggc_mark_tree (TREE_REALPART (t));
      ggc_mark_tree (TREE_IMAGPART (t));
      break;

    case STRING_CST:
      ggc_mark_string (TREE_STRING_POINTER (t));
      break;

    case PARM_DECL:
      ggc_mark_rtx (DECL_INCOMING_RTL (t));
      break;

    case IDENTIFIER_NODE:
      ggc_mark_string (IDENTIFIER_POINTER (t));
      lang_mark_tree (t);
      return;

    default:
      break;
    }
  
  /* But in general we can handle them by class.  */
  switch (TREE_CODE_CLASS (TREE_CODE (t)))
    {
    case 'd': /* A decl node.  */
      ggc_mark_string (DECL_SOURCE_FILE (t));
      ggc_mark_tree (DECL_SIZE (t));
      ggc_mark_tree (DECL_NAME (t));
      ggc_mark_tree (DECL_CONTEXT (t));
      ggc_mark_tree (DECL_ARGUMENTS (t));
      ggc_mark_tree (DECL_RESULT (t));
      ggc_mark_tree (DECL_INITIAL (t));
      ggc_mark_tree (DECL_ABSTRACT_ORIGIN (t));
      ggc_mark_tree (DECL_ASSEMBLER_NAME (t));
      ggc_mark_tree (DECL_SECTION_NAME (t));
      ggc_mark_tree (DECL_MACHINE_ATTRIBUTES (t));
      ggc_mark_rtx (DECL_RTL (t));
      ggc_mark_rtx (DECL_LIVE_RANGE_RTL (t));
      ggc_mark_tree (DECL_VINDEX (t));
      lang_mark_tree (t);
      break;

    case 't': /* A type node.  */
      ggc_mark_tree (TYPE_SIZE (t));
      ggc_mark_tree (TYPE_SIZE_UNIT (t));
      ggc_mark_tree (TYPE_ATTRIBUTES (t));
      ggc_mark_tree (TYPE_VALUES (t));
      ggc_mark_tree (TYPE_POINTER_TO (t));
      ggc_mark_tree (TYPE_REFERENCE_TO (t));
      ggc_mark_tree (TYPE_NAME (t));
      ggc_mark_tree (TYPE_MIN_VALUE (t));
      ggc_mark_tree (TYPE_MAX_VALUE (t));
      ggc_mark_tree (TYPE_NEXT_VARIANT (t));
      ggc_mark_tree (TYPE_MAIN_VARIANT (t));
      ggc_mark_tree (TYPE_BINFO (t));
      ggc_mark_tree (TYPE_NONCOPIED_PARTS (t));
      ggc_mark_tree (TYPE_CONTEXT (t));
      lang_mark_tree (t);
      break;

    case 'b': /* A lexical block.  */
      ggc_mark_tree (BLOCK_VARS (t));
      ggc_mark_tree (BLOCK_SUBBLOCKS (t));
      ggc_mark_tree (BLOCK_SUPERCONTEXT (t));
      ggc_mark_tree (BLOCK_ABSTRACT_ORIGIN (t));
      break;

    case 'c': /* A constant.  */
      ggc_mark_rtx (TREE_CST_RTL (t));
      break;

    case 'r': case '<': case '1':
    case '2': case 'e': case 's': /* Expressions.  */
      {
	int i = tree_code_length[TREE_CODE (t)];
	while (--i >= 0)
	  ggc_mark_tree (TREE_OPERAND (t, i));
	break;
      }

    case 'x':
      lang_mark_tree (t);
      break;
    }
}

/* Mark all the elements of the varray V, which contains trees.  */

void
ggc_mark_tree_varray (v)
     varray_type v;
{
  int i;

  if (v)
    for (i = v->num_elements - 1; i >= 0; --i) 
      ggc_mark_tree (VARRAY_TREE (v, i));
}

/* Mark the hash table-entry HE.  It's key field is really a tree.  */

static boolean
ggc_mark_tree_hash_table_entry (he, k)
     struct hash_entry *he;
     hash_table_key k ATTRIBUTE_UNUSED;
{
  ggc_mark_tree ((tree) he->key);
  return true;
}

/* Mark all the elements of the hash-table H, which contains trees.  */

void
ggc_mark_tree_hash_table (ht)
     struct hash_table *ht;
{
  hash_traverse (ht, ggc_mark_tree_hash_table_entry, /*info=*/0);
}

/* Allocation wrappers.  */

char *
ggc_alloc_string (contents, length)
     const char *contents;
     int length;
{
  char *string;

  if (length < 0)
    {
      if (contents == NULL)
	return NULL;
      length = strlen (contents);
    }

  string = (char *) ggc_alloc_obj (length + 1, 0);
  if (contents != NULL)
    memcpy (string, contents, length);
  string[length] = 0;

  return string;
}