expr.c

gcc-2.95.3 Linux下最常用的C编译器

	{
	  count--;
	  if (stack_pointer == 1 || count <= 0)
	    fatal ("stack underflow");
	  type = stack_type_map[stack_pointer - 2];
	}
      val = pop_value (type);
      count--;
    }
}

/* Implement the 'swap' operator (to swap two top stack slots). */

static void
java_stack_swap ()
{
  tree type1, type2;
  rtx temp;
  tree decl1, decl2;

  if (stack_pointer < 2
      || (type1 = stack_type_map[stack_pointer - 1]) == TYPE_UNKNOWN
      || (type2 = stack_type_map[stack_pointer - 2]) == TYPE_UNKNOWN
      || type1 == TYPE_SECOND || type2 == TYPE_SECOND
      || TYPE_IS_WIDE (type1) || TYPE_IS_WIDE (type2))
    fatal ("bad stack swap");

  flush_quick_stack ();
  decl1 = find_stack_slot (stack_pointer - 1, type1);
  decl2 = find_stack_slot (stack_pointer - 2, type2);
  temp = copy_to_reg (DECL_RTL (decl1));
  emit_move_insn (DECL_RTL (decl1), DECL_RTL (decl2));
  emit_move_insn (DECL_RTL (decl2), temp);
  stack_type_map[stack_pointer - 1] = type2;
  stack_type_map[stack_pointer - 2] = type1;
}

static void
java_stack_dup (size, offset)
     int size, offset;
{
  int low_index = stack_pointer - size - offset;
  int dst_index;
  if (low_index < 0)
    error ("stack underflow - dup* operation");

  flush_quick_stack ();

  stack_pointer += size;
  dst_index = stack_pointer;

  for (dst_index = stack_pointer;  --dst_index >= low_index; )
    {
      tree type;
      int src_index = dst_index - size;
      if (src_index < low_index)
	src_index = dst_index + size + offset;
      type = stack_type_map [src_index];
      if (type == TYPE_SECOND)
	{
	  if (src_index <= low_index)
	    fatal ("dup operation splits 64-bit number");
	  stack_type_map[dst_index] = type;
	  src_index--;  dst_index--;
	  type = stack_type_map[src_index];
	  if (! TYPE_IS_WIDE (type))
            fatal ("internal error - dup operation");
	}
      else if (TYPE_IS_WIDE (type))
	fatal ("internal error - dup operation");
      if (src_index != dst_index)
	{
	  tree src_decl = find_stack_slot (src_index, type);
	  tree dst_decl = find_stack_slot (dst_index, type);
	  emit_move_insn (DECL_RTL (dst_decl), DECL_RTL (src_decl));
	  stack_type_map[dst_index] = type;
	}
    }
}

/* Calls _Jv_Throw.  Discard the contents of the value stack. */

static tree
build_java_athrow (node)
    tree node;
{
  tree call;

  call = build (CALL_EXPR,
		void_type_node,
		build_address_of (throw_node),
		build_tree_list (NULL_TREE, node),
		NULL_TREE);
  TREE_SIDE_EFFECTS (call) = 1;
  expand_expr_stmt (call);
  java_stack_pop (stack_pointer);
}

/* Implementation for jsr/ret */

static void
build_java_jsr (where, ret)
    tree where;
    tree ret;
{
  tree ret_label = fold (build1 (ADDR_EXPR, return_address_type_node, ret));
  push_value (ret_label);
  flush_quick_stack ();
  expand_goto (where);
  expand_label (ret);
}

static void
build_java_ret (location)
  tree location;
{
  expand_computed_goto (location);
}
 
/* Implementation of operations on array: new, load, store, length */

/* Array core info access macros */

#define JAVA_ARRAY_LENGTH_OFFSET(A)					   \
  size_binop (CEIL_DIV_EXPR, 						   \
	      (DECL_FIELD_BITPOS					   \
		  (TREE_CHAIN (TYPE_FIELDS (TREE_TYPE (TREE_TYPE (A)))))), \
              size_int (BITS_PER_UNIT))

tree
decode_newarray_type (atype)
  int atype;
{
  switch (atype)
    {
    case 4:  return boolean_type_node;
    case 5:  return char_type_node;
    case 6:  return float_type_node;
    case 7:  return double_type_node;
    case 8:  return byte_type_node;
    case 9:  return short_type_node;
    case 10: return int_type_node;
    case 11: return long_type_node;
    default: return NULL_TREE;
    }
}

/* Map primitive type to the code used by OPCODE_newarray. */

int
encode_newarray_type (type)
     tree type;
{
  if (type == boolean_type_node)
    return 4;
  else if (type == char_type_node)
    return 5;
  else if (type == float_type_node)
    return 6;
  else if (type == double_type_node)
    return 7;
  else if (type == byte_type_node)
    return 8;
  else if (type == short_type_node)
    return 9;
  else if (type == int_type_node)
    return 10;
  else if (type == long_type_node)
    return 11;
  else
    fatal ("Can't compute type code - patch_newarray");
}

/* Build a call to _Jv_ThrowBadArrayIndex(), the
   ArrayIndexOfBoundsException exception handler.  */

static tree
build_java_throw_out_of_bounds_exception (index)
    tree index;
{
  tree node = build (CALL_EXPR, int_type_node,
		     build_address_of (soft_badarrayindex_node), 
		     build_tree_list (NULL_TREE, index), NULL_TREE);
  TREE_SIDE_EFFECTS (node) = 1;	/* Allows expansion within ANDIF */
  return (node);
}

/* Return the length of an array. Doesn't perform any checking on the nature
   or value of the array NODE. May be used to implement some bytecodes.  */

tree
build_java_array_length_access (node)
    tree node;
{
  tree type = TREE_TYPE (node);
  HOST_WIDE_INT length;
  if (!is_array_type_p (type))
    fatal ("array length on a non-array reference");
  length = java_array_type_length (type);
  if (length >= 0)
    return build_int_2 (length, 0);
  return fold (build1 (INDIRECT_REF,
		       int_type_node,
		       fold (build (PLUS_EXPR, ptr_type_node,
				    node, 
				    JAVA_ARRAY_LENGTH_OFFSET(node)))));
}

/* Optionally checks an array against the NULL pointer, eventually throwing a
   NullPointerException. It could replace signal handling, but tied to NULL.
   ARG1: the pointer to check, ARG2: the expression to use if
   the pointer is non-null and ARG3 the type that should be returned.   */

tree
build_java_arraynull_check (node, expr, type)
    tree node ATTRIBUTE_UNUSED;
    tree expr;
    tree type ATTRIBUTE_UNUSED;
{
#if 0
  static int java_array_access_throws_null_exception = 0;
  node = ???;
  if (java_array_access_throws_null_exception)
      return (build (COND_EXPR, 
		     type,
		     build (EQ_EXPR, int_type_node, node, null_pointer_node),
		     build_java_athrow (node), expr ));
  else
#endif
      return (expr);
}

static tree
java_array_data_offset (array)
     tree array;
{
  tree array_type = TREE_TYPE (TREE_TYPE (array));
  tree data_fld = TREE_CHAIN (TREE_CHAIN (TYPE_FIELDS (array_type)));
  if (data_fld == NULL_TREE)
    return size_in_bytes (array_type);
  else
    return build_int_2 (TREE_INT_CST_LOW (DECL_FIELD_BITPOS (data_fld))
			/ BITS_PER_UNIT, 0);
}

/* Implement array indexing (either as l-value or r-value).
   Returns a tree for ARRAY[INDEX], assume TYPE is the element type.
   Optionally performs bounds checking and/or test to NULL.
   At this point, ARRAY should have been verified as an array.  */

tree
build_java_arrayaccess (array, type, index)
    tree array, type, index;
{
  tree arith, node, throw = NULL_TREE;

  arith = fold (build (PLUS_EXPR, int_type_node,
		       java_array_data_offset (array),
		       fold (build (MULT_EXPR, int_type_node,
				    index, size_in_bytes(type)))));

  if (flag_bounds_check)
    {
      /* Generate:
       * (unsigned jint) INDEX >= (unsigned jint) LEN
       *    && throw ArrayIndexOutOfBoundsException.
       * Note this is equivalent to and more efficient than:
       * INDEX < 0 || INDEX >= LEN && throw ... */
      tree test;
      tree len = build_java_array_length_access (array);
      TREE_TYPE (len) = unsigned_int_type_node;
      test = fold (build (GE_EXPR, boolean_type_node, 
			       convert (unsigned_int_type_node, index),
			       len));
      if (! integer_zerop (test))
	{
	  throw = build (TRUTH_ANDIF_EXPR, int_type_node, test,
			 build_java_throw_out_of_bounds_exception (index));
	  /* allows expansion within COMPOUND */
	  TREE_SIDE_EFFECTS( throw ) = 1;
	}
    }

  node = build1 (INDIRECT_REF, type, 
		 fold (build (PLUS_EXPR, ptr_type_node, 
			      array, 
			      (throw ? build (COMPOUND_EXPR, int_type_node, 
					      throw, arith )
			             : arith))));

  return (fold (build_java_arraynull_check (array, node, type)));
}

/* Makes sure that INDEXED_TYPE is appropriate. If not, make it from
   ARRAY_NODE. This function is used to retrieve something less vague than
   a pointer type when indexing the first dimension of something like [[<t>.
   May return a corrected type, if necessary, otherwise INDEXED_TYPE is
   return unchanged.
   As a side effect, it also makes sure that ARRAY_NODE is an array.  */

static tree
build_java_check_indexed_type (array_node, indexed_type)
    tree array_node;
    tree indexed_type;
{
  tree elt_type;

  if (!is_array_type_p (TREE_TYPE (array_node)))
    fatal ("array indexing on a non-array reference");

  elt_type = (TYPE_ARRAY_ELEMENT (TREE_TYPE (TREE_TYPE (array_node))));

  if (indexed_type == ptr_type_node )
      return promote_type (elt_type);

  /* BYTE/BOOLEAN store and load are used for both type */
  if (indexed_type == byte_type_node && elt_type == boolean_type_node )
    return boolean_type_node;

  if (indexed_type != elt_type )
    fatal ("type array element mismatch");
  else
    return indexed_type;
}

/* newarray triggers a call to _Jv_NewArray. This function should be called
   with an integer code (the type of array to create) and get from the stack
   the size of the dimmension.  */

tree
build_newarray (atype_value, length)
     int atype_value;
     tree length;
{
  tree type = build_java_array_type (decode_newarray_type (atype_value),
				     TREE_CODE (length) == INTEGER_CST
				     ? TREE_INT_CST_LOW (length)
				     : -1);
  return build (CALL_EXPR, promote_type (type),
		build_address_of (soft_newarray_node),
		tree_cons (NULL_TREE, 
			   build_int_2 (atype_value, 0),
			   build_tree_list (NULL_TREE, length)),
		NULL_TREE);
}

/* Generates anewarray from a given CLASS_TYPE. Gets from the stack the size
   of the dimension. */

tree
build_anewarray (class_type, length)
    tree class_type;
    tree length;
{
  tree type = build_java_array_type (class_type,
				     TREE_CODE (length) == INTEGER_CST
				     ? TREE_INT_CST_LOW (length)
				     : -1);
  return build (CALL_EXPR, promote_type (type),
		build_address_of (soft_anewarray_node),
		tree_cons (NULL_TREE, length,
			   tree_cons (NULL_TREE, build_class_ref (class_type),
				      build_tree_list (NULL_TREE,
						       null_pointer_node))),
		NULL_TREE);
}

/* Return a node the evaluates 'new TYPE[LENGTH]'. */

tree
build_new_array (type, length)
     tree type;
     tree length;
{
  if (JPRIMITIVE_TYPE_P (type))
    return build_newarray (encode_newarray_type (type), length);
  else
    return build_anewarray (TREE_TYPE (type), length);
}

/* Generates a call to _Jv_NewMultiArray. multianewarray expects a
   class pointer, a number of dimensions and the matching number of
   dimensions. The argument list is NULL terminated.  */

static void
expand_java_multianewarray (class_type, ndim)
    tree class_type;
    int  ndim;
{
  int i;
  tree args = build_tree_list( NULL_TREE, null_pointer_node );

  for( i = 0; i < ndim; i++ )
    args = tree_cons (NULL_TREE, pop_value (int_type_node), args);

  push_value (build (CALL_EXPR,
		     promote_type (class_type),
		     build_address_of (soft_multianewarray_node),
		     tree_cons (NULL_TREE, build_class_ref (class_type),
				tree_cons (NULL_TREE, 
					   build_int_2 (ndim, 0), args )),
		     NULL_TREE));
}

/*  ARRAY[INDEX] <- RHS. build_java_check_indexed_type makes sure that
    ARRAY is an array type. May expand some bound checking and NULL
    pointer checking. RHS_TYPE_NODE we are going to store. In the case
    of the CHAR/BYTE/BOOLEAN SHORT, the type popped of the stack is an
    INT. In those cases, we make the convertion.

    if ARRAy is a reference type, the assignment is checked at run-time
    to make sure that the RHS can be assigned to the array element
    type. It is not necessary to generate this code if ARRAY is final.  */

static void
expand_java_arraystore (rhs_type_node)
     tree rhs_type_node;
{
  tree rhs_node    = pop_value ((INTEGRAL_TYPE_P (rhs_type_node) 
				 && TYPE_PRECISION (rhs_type_node) <= 32) ? 
				 int_type_node : rhs_type_node);
  tree index = pop_value (int_type_node);
  tree array = pop_value (ptr_type_node);

  rhs_type_node    = build_java_check_indexed_type (array, rhs_type_node);

  flush_quick_stack ();

  index = save_expr (index);
  array = save_expr (array);

  if (TREE_CODE (rhs_type_node) == POINTER_TYPE
      && !CLASS_FINAL (TYPE_NAME (TREE_TYPE (rhs_type_node))))
    {
      tree check = build (CALL_EXPR, void_type_node,
			  build_address_of (soft_checkarraystore_node),
			  tree_cons (NULL_TREE, array,
				     build_tree_list (NULL_TREE, rhs_node)),
			  NULL_TREE);