tree.c

GUN开源阻止下的编译器GCC

  TREE_TYPE (t) = build_complex_type (TREE_TYPE (real));
  TREE_OVERFLOW (t) = TREE_OVERFLOW (real) | TREE_OVERFLOW (imag);
  TREE_CONSTANT_OVERFLOW (t)
    = TREE_CONSTANT_OVERFLOW (real) | TREE_CONSTANT_OVERFLOW (imag);
  return t;
}

/* Build a newly constructed TREE_VEC node of length LEN.  */
tree
make_tree_vec (len)
     int len;
{
  register tree t;
  register int length = (len-1) * sizeof (tree) + sizeof (struct tree_vec);
  register struct obstack *obstack = current_obstack;
  register int i;

#ifdef GATHER_STATISTICS
  tree_node_counts[(int)vec_kind]++;
  tree_node_sizes[(int)vec_kind] += length;
#endif

  t = (tree) obstack_alloc (obstack, length);

  for (i = (length / sizeof (int)) - 1; i >= 0; i--)
    ((int *) t)[i] = 0;

  TREE_SET_CODE (t, TREE_VEC);
  TREE_VEC_LENGTH (t) = len;
  if (obstack == &permanent_obstack)
    TREE_PERMANENT (t) = 1;

  return t;
}

/* Return 1 if EXPR is the integer constant zero or a complex constant
   of zero.  */

int
integer_zerop (expr)
     tree expr;
{
  STRIP_NOPS (expr);

  return ((TREE_CODE (expr) == INTEGER_CST
	   && TREE_INT_CST_LOW (expr) == 0
	   && TREE_INT_CST_HIGH (expr) == 0)
	  || (TREE_CODE (expr) == COMPLEX_CST
	      && integer_zerop (TREE_REALPART (expr))
	      && integer_zerop (TREE_IMAGPART (expr))));
}

/* Return 1 if EXPR is the integer constant one or the corresponding
   complex constant.  */

int
integer_onep (expr)
     tree expr;
{
  STRIP_NOPS (expr);

  return ((TREE_CODE (expr) == INTEGER_CST
	   && TREE_INT_CST_LOW (expr) == 1
	   && TREE_INT_CST_HIGH (expr) == 0)
	  || (TREE_CODE (expr) == COMPLEX_CST
	      && integer_onep (TREE_REALPART (expr))
	      && integer_zerop (TREE_IMAGPART (expr))));
}

/* Return 1 if EXPR is an integer containing all 1's in as much precision as
   it contains.  Likewise for the corresponding complex constant.  */

int
integer_all_onesp (expr)
     tree expr;
{
  register int prec;
  register int uns;

  STRIP_NOPS (expr);

  if (TREE_CODE (expr) == COMPLEX_CST
      && integer_all_onesp (TREE_REALPART (expr))
      && integer_zerop (TREE_IMAGPART (expr)))
    return 1;

  else if (TREE_CODE (expr) != INTEGER_CST)
    return 0;

  uns = TREE_UNSIGNED (TREE_TYPE (expr));
  if (!uns)
    return TREE_INT_CST_LOW (expr) == -1 && TREE_INT_CST_HIGH (expr) == -1;

  /* Note that using TYPE_PRECISION here is wrong.  We care about the
     actual bits, not the (arbitrary) range of the type.  */
  prec = GET_MODE_BITSIZE (TYPE_MODE (TREE_TYPE (expr)));
  if (prec >= HOST_BITS_PER_WIDE_INT)
    {
      int high_value, shift_amount;

      shift_amount = prec - HOST_BITS_PER_WIDE_INT;

      if (shift_amount > HOST_BITS_PER_WIDE_INT)
	/* Can not handle precisions greater than twice the host int size.  */
	abort ();
      else if (shift_amount == HOST_BITS_PER_WIDE_INT)
	/* Shifting by the host word size is undefined according to the ANSI
	   standard, so we must handle this as a special case.  */
	high_value = -1;
      else
	high_value = ((HOST_WIDE_INT) 1 << shift_amount) - 1;

      return TREE_INT_CST_LOW (expr) == -1
	&& TREE_INT_CST_HIGH (expr) == high_value;
    }
  else
    return TREE_INT_CST_LOW (expr) == ((HOST_WIDE_INT) 1 << prec) - 1;
}

/* Return 1 if EXPR is an integer constant that is a power of 2 (i.e., has only
   one bit on).  */

int
integer_pow2p (expr)
     tree expr;
{
  HOST_WIDE_INT high, low;

  STRIP_NOPS (expr);

  if (TREE_CODE (expr) == COMPLEX_CST
      && integer_pow2p (TREE_REALPART (expr))
      && integer_zerop (TREE_IMAGPART (expr)))
    return 1;

  if (TREE_CODE (expr) != INTEGER_CST)
    return 0;

  high = TREE_INT_CST_HIGH (expr);
  low = TREE_INT_CST_LOW (expr);

  if (high == 0 && low == 0)
    return 0;

  return ((high == 0 && (low & (low - 1)) == 0)
	  || (low == 0 && (high & (high - 1)) == 0));
}

/* Return 1 if EXPR is the real constant zero.  */

int
real_zerop (expr)
     tree expr;
{
  STRIP_NOPS (expr);

  return ((TREE_CODE (expr) == REAL_CST
	   && REAL_VALUES_EQUAL (TREE_REAL_CST (expr), dconst0))
	  || (TREE_CODE (expr) == COMPLEX_CST
	      && real_zerop (TREE_REALPART (expr))
	      && real_zerop (TREE_IMAGPART (expr))));
}

/* Return 1 if EXPR is the real constant one in real or complex form.  */

int
real_onep (expr)
     tree expr;
{
  STRIP_NOPS (expr);

  return ((TREE_CODE (expr) == REAL_CST
	   && REAL_VALUES_EQUAL (TREE_REAL_CST (expr), dconst1))
	  || (TREE_CODE (expr) == COMPLEX_CST
	      && real_onep (TREE_REALPART (expr))
	      && real_zerop (TREE_IMAGPART (expr))));
}

/* Return 1 if EXPR is the real constant two.  */

int
real_twop (expr)
     tree expr;
{
  STRIP_NOPS (expr);

  return ((TREE_CODE (expr) == REAL_CST
	   && REAL_VALUES_EQUAL (TREE_REAL_CST (expr), dconst2))
	  || (TREE_CODE (expr) == COMPLEX_CST
	      && real_twop (TREE_REALPART (expr))
	      && real_zerop (TREE_IMAGPART (expr))));
}

/* Nonzero if EXP is a constant or a cast of a constant.  */
 
int
really_constant_p (exp)
     tree exp;
{
  /* This is not quite the same as STRIP_NOPS.  It does more.  */
  while (TREE_CODE (exp) == NOP_EXPR
	 || TREE_CODE (exp) == CONVERT_EXPR
	 || TREE_CODE (exp) == NON_LVALUE_EXPR)
    exp = TREE_OPERAND (exp, 0);
  return TREE_CONSTANT (exp);
}

/* Return first list element whose TREE_VALUE is ELEM.
   Return 0 if ELEM is not in LIST.  */

tree
value_member (elem, list)
     tree elem, list;
{
  while (list)
    {
      if (elem == TREE_VALUE (list))
	return list;
      list = TREE_CHAIN (list);
    }
  return NULL_TREE;
}

/* Return first list element whose TREE_PURPOSE is ELEM.
   Return 0 if ELEM is not in LIST.  */

tree
purpose_member (elem, list)
     tree elem, list;
{
  while (list)
    {
      if (elem == TREE_PURPOSE (list))
	return list;
      list = TREE_CHAIN (list);
    }
  return NULL_TREE;
}

/* Return first list element whose BINFO_TYPE is ELEM.
   Return 0 if ELEM is not in LIST.  */

tree
binfo_member (elem, list)
     tree elem, list;
{
  while (list)
    {
      if (elem == BINFO_TYPE (list))
	return list;
      list = TREE_CHAIN (list);
    }
  return NULL_TREE;
}

/* Return nonzero if ELEM is part of the chain CHAIN. */

int
chain_member (elem, chain)
     tree elem, chain;
{
  while (chain)
    {
      if (elem == chain)
	return 1;
      chain = TREE_CHAIN (chain);
    }

  return 0;
}

/* Return nonzero if ELEM is equal to TREE_VALUE (CHAIN) for any piece of
   chain CHAIN. */
/* ??? This function was added for machine specific attributes but is no
   longer used.  It could be deleted if we could confirm all front ends
   don't use it.  */

int
chain_member_value (elem, chain)
     tree elem, chain;
{
  while (chain)
    {
      if (elem == TREE_VALUE (chain))
	return 1;
      chain = TREE_CHAIN (chain);
    }

  return 0;
}

/* Return nonzero if ELEM is equal to TREE_PURPOSE (CHAIN)
   for any piece of chain CHAIN. */
/* ??? This function was added for machine specific attributes but is no
   longer used.  It could be deleted if we could confirm all front ends
   don't use it.  */

int
chain_member_purpose (elem, chain)
     tree elem, chain;
{
  while (chain)
    {
      if (elem == TREE_PURPOSE (chain))
	return 1;
      chain = TREE_CHAIN (chain);
    }

  return 0;
}

/* Return the length of a chain of nodes chained through TREE_CHAIN.
   We expect a null pointer to mark the end of the chain.
   This is the Lisp primitive `length'.  */

int
list_length (t)
     tree t;
{
  register tree tail;
  register int len = 0;

  for (tail = t; tail; tail = TREE_CHAIN (tail))
    len++;

  return len;
}

/* Concatenate two chains of nodes (chained through TREE_CHAIN)
   by modifying the last node in chain 1 to point to chain 2.
   This is the Lisp primitive `nconc'.  */

tree
chainon (op1, op2)
     tree op1, op2;
{

  if (op1)
    {
      register tree t1;
      register tree t2;

      for (t1 = op1; TREE_CHAIN (t1); t1 = TREE_CHAIN (t1))
	;
      TREE_CHAIN (t1) = op2;
      for (t2 = op2; t2; t2 = TREE_CHAIN (t2))
        if (t2 == t1)
          abort ();  /* Circularity created.  */
      return op1;
    }
  else return op2;
}

/* Return the last node in a chain of nodes (chained through TREE_CHAIN).  */

tree
tree_last (chain)
     register tree chain;
{
  register tree next;
  if (chain)
    while (next = TREE_CHAIN (chain))
      chain = next;
  return chain;
}

/* Reverse the order of elements in the chain T,
   and return the new head of the chain (old last element).  */

tree
nreverse (t)
     tree t;
{
  register tree prev = 0, decl, next;
  for (decl = t; decl; decl = next)
    {
      next = TREE_CHAIN (decl);
      TREE_CHAIN (decl) = prev;
      prev = decl;
    }
  return prev;
}

/* Given a chain CHAIN of tree nodes,
   construct and return a list of those nodes.  */

tree
listify (chain)
     tree chain;
{
  tree result = NULL_TREE;
  tree in_tail = chain;
  tree out_tail = NULL_TREE;

  while (in_tail)
    {
      tree next = tree_cons (NULL_TREE, in_tail, NULL_TREE);
      if (out_tail)
	TREE_CHAIN (out_tail) = next;
      else
	result = next;
      out_tail = next;
      in_tail = TREE_CHAIN (in_tail);
    }

  return result;
}

/* Return a newly created TREE_LIST node whose
   purpose and value fields are PARM and VALUE.  */

tree
build_tree_list (parm, value)
     tree parm, value;
{
  register tree t = make_node (TREE_LIST);
  TREE_PURPOSE (t) = parm;
  TREE_VALUE (t) = value;
  return t;
}

/* Similar, but build on the temp_decl_obstack.  */

tree
build_decl_list (parm, value)
     tree parm, value;
{
  register tree node;
  register struct obstack *ambient_obstack = current_obstack;
  current_obstack = &temp_decl_obstack;
  node = build_tree_list (parm, value);
  current_obstack = ambient_obstack;
  return node;
}

/* Return a newly created TREE_LIST node whose
   purpose and value fields are PARM and VALUE
   and whose TREE_CHAIN is CHAIN.  */

tree
tree_cons (purpose, value, chain)
     tree purpose, value, chain;
{
#if 0
  register tree node = make_node (TREE_LIST);
#else
  register int i;
  register tree node = (tree) obstack_alloc (current_obstack, sizeof (struct tree_list));
#ifdef GATHER_STATISTICS
  tree_node_counts[(int)x_kind]++;
  tree_node_sizes[(int)x_kind] += sizeof (struct tree_list);
#endif

  for (i = (sizeof (struct tree_common) / sizeof (int)) - 1; i >= 0; i--)
    ((int *) node)[i] = 0;

  TREE_SET_CODE (node, TREE_LIST);
  if (current_obstack == &permanent_obstack)
    TREE_PERMANENT (node) = 1;
#endif

  TREE_CHAIN (node) = chain;
  TREE_PURPOSE (node) = purpose;
  TREE_VALUE (node) = value;
  return node;
}

/* Similar, but build on the temp_decl_obstack.  */

tree
decl_tree_cons (purpose, value, chain)
     tree purpose, value, chain;
{
  register tree node;
  register struct obstack *ambient_obstack = current_obstack;
  current_obstack = &temp_decl_obstack;
  node = tree_cons (purpose, value, chain);
  current_obstack = ambient_obstack;
  return node;
}