minwin-gcc-5-2/gcc/java/typeck.c

/* Handle types for the GNU compiler for the Java(TM) language.
   Copyright (C) 1996-2015 Free Software Foundation, Inc.

This file is part of GCC.

GCC 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 3, or (at your option)
any later version.

GCC 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 GCC; see the file COPYING3.  If not see
<http://www.gnu.org/licenses/>.  

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 Per Bothner <bothner@cygnus.com> */

#include "config.h"
#include "system.h"
#include "coretypes.h"
#include "hash-set.h"
#include "machmode.h"
#include "vec.h"
#include "double-int.h"
#include "input.h"
#include "alias.h"
#include "symtab.h"
#include "options.h"
#include "wide-int.h"
#include "inchash.h"
#include "tree.h"
#include "fold-const.h"
#include "stor-layout.h"
#include "stringpool.h"
#include "obstack.h"
#include "flags.h"
#include "java-tree.h"
#include "jcf.h"
#include "convert.h"
#include "diagnostic-core.h"
#include "ggc.h"

static tree convert_ieee_real_to_integer (tree, tree);
static tree parse_signature_type (const unsigned char **,
				  const unsigned char *);
static tree lookup_do (tree, int, tree, tree, tree (*)(tree));
static tree build_null_signature (tree);

tree * type_map;

/* Set the type of the local variable with index SLOT to TYPE. */

void
set_local_type (int slot, tree type)
{
  int max_locals = DECL_MAX_LOCALS(current_function_decl);
  int nslots = TYPE_IS_WIDE (type) ? 2 : 1;

  gcc_assert (slot >= 0 && (slot + nslots - 1 < max_locals));

  type_map[slot] = type;
  while (--nslots > 0)
    type_map[++slot] = void_type_node;
}

/* Convert an IEEE real to an integer type.  The result of such a
   conversion when the source operand is a NaN isn't defined by
   IEEE754, but by the Java language standard: it must be zero.  Also,
   overflows must be clipped to within range.  This conversion
   produces something like:

      ((expr >= (float)MAX_INT)
       ? MAX_INT 
       : ((expr <= (float)MIN_INT)
	  ? MIN_INT
	  : ((expr != expr)
	     ? 0 
	     : (int)expr))) */

static tree
convert_ieee_real_to_integer (tree type, tree expr)
{
  tree result;
  expr = save_expr (expr);

  result = fold_build3 (COND_EXPR, type,
			fold_build2 (NE_EXPR, boolean_type_node, expr, expr),
			 convert (type, integer_zero_node),
			 convert_to_integer (type, expr));
  
  result = fold_build3 (COND_EXPR, type, 
			fold_build2 (LE_EXPR, boolean_type_node, expr, 
				     convert (TREE_TYPE (expr), 
					      TYPE_MIN_VALUE (type))),
			TYPE_MIN_VALUE (type),
			result);
  
  result = fold_build3 (COND_EXPR, type,
			fold_build2 (GE_EXPR, boolean_type_node, expr, 
				     convert (TREE_TYPE (expr), 
					      TYPE_MAX_VALUE (type))),
			TYPE_MAX_VALUE (type),
			result);

  return result;
}  

/* Create an expression whose value is that of EXPR,
   converted to type TYPE.  The TREE_TYPE of the value
   is always TYPE.  This function implements all reasonable
   conversions; callers should filter out those that are
   not permitted by the language being compiled.  */

tree
convert (tree type, tree expr)
{
  enum tree_code code = TREE_CODE (type);

  if (!expr)
   return error_mark_node;

  if (type == TREE_TYPE (expr)
      || TREE_CODE (expr) == ERROR_MARK)
    return expr;
  if (TREE_CODE (TREE_TYPE (expr)) == ERROR_MARK)
    return error_mark_node;
  if (code == VOID_TYPE)
    return build1 (CONVERT_EXPR, type, expr);
  if (code == BOOLEAN_TYPE)
    return fold_convert (type, expr);
  if (code == INTEGER_TYPE)
    {
      if (type == char_type_node || type == promoted_char_type_node)
	return fold_convert (type, expr);
      if ((really_constant_p (expr) || ! flag_unsafe_math_optimizations)
	  && TREE_CODE (TREE_TYPE (expr)) == REAL_TYPE)
	return convert_ieee_real_to_integer (type, expr);
      else
	{
	  /* fold very helpfully sets the overflow status if a type
	     overflows in a narrowing integer conversion, but Java
	     doesn't care.  */
	  tree tmp = fold (convert_to_integer (type, expr));
	  if (TREE_CODE (tmp) == INTEGER_CST)
	    TREE_OVERFLOW (tmp) = 0;
	  return tmp;
	}
    }	  
  if (code == REAL_TYPE)
    return fold (convert_to_real (type, expr));
  if (code == POINTER_TYPE)
    return fold (convert_to_pointer (type, expr));
  error ("conversion to non-scalar type requested");
  return error_mark_node;
}


/* Return a data type that has machine mode MODE.
   If the mode is an integer,
   then UNSIGNEDP selects between signed and unsigned types.  */

tree
java_type_for_mode (machine_mode mode, int unsignedp)
{
  if (mode == TYPE_MODE (int_type_node))
    return unsignedp ? unsigned_int_type_node : int_type_node;
  if (mode == TYPE_MODE (long_type_node))
    return unsignedp ? unsigned_long_type_node : long_type_node;
  if (mode == TYPE_MODE (short_type_node))
    return unsignedp ? unsigned_short_type_node : short_type_node;
  if (mode == TYPE_MODE (byte_type_node))
    return unsignedp ? unsigned_byte_type_node : byte_type_node;
  if (mode == TYPE_MODE (float_type_node))
    return float_type_node;
  if (mode == TYPE_MODE (double_type_node))
    return double_type_node;

  return 0;
}

/* Return an integer type with BITS bits of precision,
   that is unsigned if UNSIGNEDP is nonzero, otherwise signed.  */

tree
java_type_for_size (unsigned bits, int unsignedp)
{
  if (bits <= TYPE_PRECISION (byte_type_node))
    return unsignedp ? unsigned_byte_type_node : byte_type_node;
  if (bits <= TYPE_PRECISION (short_type_node))
    return unsignedp ? unsigned_short_type_node : short_type_node;
  if (bits <= TYPE_PRECISION (int_type_node))
    return unsignedp ? unsigned_int_type_node : int_type_node;
  if (bits <= TYPE_PRECISION (long_type_node))
    return unsignedp ? unsigned_long_type_node : long_type_node;
  return 0;
}

/* Thorough checking of the arrayness of TYPE.  */

int
is_array_type_p (tree type)
{
  return TREE_CODE (type) == POINTER_TYPE
    && TREE_CODE (TREE_TYPE (type)) == RECORD_TYPE
    && TYPE_ARRAY_P (TREE_TYPE (type));
}

/* Return the length of a Java array type.
   Return -1 if the length is unknown or non-constant. */

HOST_WIDE_INT
java_array_type_length (tree array_type)
{
  tree arfld;
  if (TREE_CODE (array_type) == POINTER_TYPE)
    array_type = TREE_TYPE (array_type);
  arfld = DECL_CHAIN (DECL_CHAIN (TYPE_FIELDS (array_type)));
  if (arfld != NULL_TREE)
    {
      tree index_type = TYPE_DOMAIN (TREE_TYPE (arfld));
      if (index_type != NULL_TREE)
	{
	  tree high = TYPE_MAX_VALUE (index_type);
	  if (TREE_CODE (high) == INTEGER_CST)
	    return TREE_INT_CST_LOW (high) + 1;
	}
    }
  return -1;
}

/* An array of unknown length will be ultimately given a length of
   -2, so that we can still have `length' producing a negative value
   even if found. This was part of an optimization aiming at removing
   `length' from static arrays. We could restore it, FIXME.  */

tree
build_prim_array_type (tree element_type, HOST_WIDE_INT length)
{
  tree index = NULL;

  if (length != -1)
    {
      tree max_index = build_int_cst (sizetype, length - 1);
      index = build_index_type (max_index);
    }
  return build_array_type (element_type, index);
}

/* Return a Java array type with a given ELEMENT_TYPE and LENGTH.
   These are hashed (shared) using IDENTIFIER_SIGNATURE_TYPE.
   The LENGTH is -1 if the length is unknown. */

tree
build_java_array_type (tree element_type, HOST_WIDE_INT length)
{
  tree sig, t, fld, atype, arfld;
  char buf[23];
  tree elsig = build_java_signature (element_type);
  tree el_name = element_type;
  buf[0] = '[';
  if (length >= 0)
    sprintf (buf+1, HOST_WIDE_INT_PRINT_DEC, length);
  else
    buf[1] = '\0';
  sig = ident_subst (IDENTIFIER_POINTER (elsig), IDENTIFIER_LENGTH (elsig),
		     buf, 0, 0, "");
  t = IDENTIFIER_SIGNATURE_TYPE (sig);
  if (t != NULL_TREE)
    return TREE_TYPE (t);
  t = make_class ();
  IDENTIFIER_SIGNATURE_TYPE (sig) = build_pointer_type (t);
  TYPE_ARRAY_P (t) = 1;

  if (TREE_CODE (el_name) == POINTER_TYPE)
    el_name = TREE_TYPE (el_name);
  el_name = TYPE_NAME (el_name);
  if (TREE_CODE (el_name) == TYPE_DECL)
    el_name = DECL_NAME (el_name);
  {
    char suffix[23];
    if (length >= 0)
      sprintf (suffix, "[%d]", (int)length); 
    else
      strcpy (suffix, "[]");
    TYPE_NAME (t) 
      = TYPE_STUB_DECL (t)
      = build_decl (input_location, TYPE_DECL,
		    identifier_subst (el_name, "", '.', '.', suffix),
                             t);
    TYPE_DECL_SUPPRESS_DEBUG (TYPE_STUB_DECL (t)) = true;
  }

  set_java_signature (t, sig);
  set_super_info (0, t, object_type_node, 0);
  if (TREE_CODE (element_type) == RECORD_TYPE)
    element_type = promote_type (element_type);
  TYPE_ARRAY_ELEMENT (t) = element_type;

  /* Add length pseudo-field. */
  fld = build_decl (input_location,
		    FIELD_DECL, get_identifier ("length"), int_type_node);
  TYPE_FIELDS (t) = fld;
  DECL_CONTEXT (fld) = t;
  FIELD_PUBLIC (fld) = 1;
  FIELD_FINAL (fld) = 1;
  TREE_READONLY (fld) = 1;

  atype = build_prim_array_type (element_type, length);
  arfld = build_decl (input_location,
		      FIELD_DECL, get_identifier ("data"), atype);
  DECL_CONTEXT (arfld) = t;
  DECL_CHAIN (fld) = arfld;
  DECL_ALIGN (arfld) = TYPE_ALIGN (element_type);

  /* We could layout_class, but that loads java.lang.Object prematurely.
   * This is called by the parser, and it is a bad idea to do load_class
   * in the middle of parsing, because of possible circularity problems. */
  push_super_field (t, object_type_node);
  layout_type (t);

  return t;
}

/* Promote TYPE to the type actually used for fields and parameters. */

tree
promote_type (tree type)
{
  switch (TREE_CODE (type))
    {
    case RECORD_TYPE:
      return build_pointer_type (type);
    case BOOLEAN_TYPE:
      if (type == boolean_type_node)
	return promoted_boolean_type_node;
      goto handle_int;
    case INTEGER_TYPE:
      if (type == char_type_node)
	return promoted_char_type_node;
    handle_int:
      if (TYPE_PRECISION (type) < TYPE_PRECISION (int_type_node))
	{
	  if (type == short_type_node)
	    return promoted_short_type_node;
	  if (type == byte_type_node)
	    return promoted_byte_type_node;
	  return int_type_node;
	}
      /* ... else fall through ... */
    default:
      return type;
    }
}

/* Parse a signature string, starting at *PTR and ending at LIMIT.
   Return the seen TREE_TYPE, updating *PTR. */

static tree
parse_signature_type (const unsigned char **ptr, const unsigned char *limit)
{
  tree type;
  gcc_assert (*ptr < limit);

  switch (**ptr)
    {
    case 'B':  (*ptr)++;  return byte_type_node;
    case 'C':  (*ptr)++;  return char_type_node;
    case 'D':  (*ptr)++;  return double_type_node;
    case 'F':  (*ptr)++;  return float_type_node;
    case 'S':  (*ptr)++;  return short_type_node;
    case 'I':  (*ptr)++;  return int_type_node;
    case 'J':  (*ptr)++;  return long_type_node;
    case 'Z':  (*ptr)++;  return boolean_type_node;
    case 'V':  (*ptr)++;  return void_type_node;
    case '[':
      for ((*ptr)++; (*ptr) < limit && ISDIGIT (**ptr); ) (*ptr)++;
      type = parse_signature_type (ptr, limit);
      type = build_java_array_type (type, -1); 
      break;
    case 'L':
      {
	const unsigned char *start = ++(*ptr);
	const unsigned char *str = start;
	for ( ; ; str++)
	  {
	    gcc_assert (str < limit);
	    if (*str == ';')
	      break;
	  }
	*ptr = str+1;
	type = lookup_class (unmangle_classname ((const char *) start, str - start));
	break;
      }
    default:
      gcc_unreachable ();
    }
  return promote_type (type);
}

/* Parse a Java "mangled" signature string, starting at SIG_STRING,
   and SIG_LENGTH bytes long.
   Return a gcc type node. */

tree
parse_signature_string (const unsigned char *sig_string, int sig_length)
{
  tree result_type;
  const unsigned char *str = sig_string;
  const unsigned char *limit = str + sig_length;

  if (str < limit && str[0] == '(')
    {
      tree argtype_list = NULL_TREE;
      str++;
      while (str < limit && str[0] != ')')
	{
	  tree argtype = parse_signature_type (&str, limit);
	  argtype_list = tree_cons (NULL_TREE, argtype, argtype_list);
	}
      if (str++, str >= limit)
	abort ();
      result_type = parse_signature_type (&str, limit);
      argtype_list = chainon (nreverse (argtype_list), end_params_node);
      result_type = build_function_type (result_type, argtype_list);
    }
  else
    result_type = parse_signature_type (&str, limit);
  if (str != limit)
    error ("junk at end of signature string");
  return result_type;
}

/* Convert a signature to its type.
 * Uses IDENTIFIER_SIGNATURE_TYPE as a cache (except for primitive types).
 */

tree
get_type_from_signature (tree signature)
{
  const unsigned char *sig = (const unsigned char *) IDENTIFIER_POINTER (signature);
  int len = IDENTIFIER_LENGTH (signature);
  tree type;
  /* Primitive types aren't cached. */
  if (len <= 1)
    return parse_signature_string (sig, len);
  type = IDENTIFIER_SIGNATURE_TYPE (signature);
  if (type == NULL_TREE)
    {
      type = parse_signature_string (sig, len);
      IDENTIFIER_SIGNATURE_TYPE (signature) = type;
    }
  return type;
}

/* Ignore signature and always return null.  Used by has_method. */

static tree
build_null_signature (tree type ATTRIBUTE_UNUSED)
{
  return NULL_TREE;
}

/* Return the signature string for the arguments of method type TYPE. */

tree
build_java_argument_signature (tree type)
{
  extern struct obstack temporary_obstack;
  tree sig = TYPE_ARGUMENT_SIGNATURE (type);
  if (sig == NULL_TREE)
    {
      tree args = TYPE_ARG_TYPES (type);
      if (TREE_CODE (type) == METHOD_TYPE)
	args = TREE_CHAIN (args);  /* Skip "this" argument. */
      for (; args != end_params_node; args = TREE_CHAIN (args))
	{
	  tree t = build_java_signature (TREE_VALUE (args));
	  obstack_grow (&temporary_obstack,
			IDENTIFIER_POINTER (t), IDENTIFIER_LENGTH (t));
	}
      obstack_1grow (&temporary_obstack, '\0');

      sig = get_identifier ((char *) obstack_base (&temporary_obstack));
      TYPE_ARGUMENT_SIGNATURE (type) = sig;
      obstack_free (&temporary_obstack, obstack_base (&temporary_obstack));
    }
  return sig;
}

/* Return the signature of the given TYPE. */

tree
build_java_signature (tree type)
{
  tree sig, t;
  while (TREE_CODE (type) == POINTER_TYPE)
    type = TREE_TYPE (type);
  MAYBE_CREATE_TYPE_TYPE_LANG_SPECIFIC (type);
  sig = TYPE_SIGNATURE (type);
  if (sig == NULL_TREE)
    {
      char sg[2];
      switch (TREE_CODE (type))
	{
	case BOOLEAN_TYPE: sg[0] = 'Z';  goto native;
	case VOID_TYPE:    sg[0] = 'V';  goto native;
	case INTEGER_TYPE:
          if (type == char_type_node || type == promoted_char_type_node)
	    {
	      sg[0] = 'C';
	      goto native;
	    }
	  switch (TYPE_PRECISION (type))
	    {
	    case  8:       sg[0] = 'B';  goto native;
	    case 16:       sg[0] = 'S';  goto native;
	    case 32:       sg[0] = 'I';  goto native;
	    case 64:       sg[0] = 'J';  goto native;
	    default:  goto bad_type;
	    }
	case REAL_TYPE:
	  switch (TYPE_PRECISION (type))
	    {
	    case 32:       sg[0] = 'F';  goto native;
	    case 64:       sg[0] = 'D';  goto native;
	    default:  goto bad_type;
	    }
	native:
	  sg[1] = 0;
	  sig = get_identifier (sg);
	  break;
	case RECORD_TYPE:
	  if (TYPE_ARRAY_P (type))
	    {
	      t = build_java_signature (TYPE_ARRAY_ELEMENT (type));
	      sig = ident_subst (IDENTIFIER_POINTER (t), IDENTIFIER_LENGTH (t),
				 "[", 0, 0, "");
	    }
	  else
	    {
	      t = DECL_NAME (TYPE_NAME (type));
	      sig = ident_subst (IDENTIFIER_POINTER (t), IDENTIFIER_LENGTH (t),
				 "L", '.', '/', ";");
	    }
	  break;
	case METHOD_TYPE:
	case FUNCTION_TYPE:
	  {
	    extern struct obstack temporary_obstack;
	    sig = build_java_argument_signature (type);
	    obstack_1grow (&temporary_obstack, '(');
	    obstack_grow (&temporary_obstack,
			  IDENTIFIER_POINTER (sig), IDENTIFIER_LENGTH (sig));
	    obstack_1grow (&temporary_obstack, ')');

	    t = build_java_signature (TREE_TYPE (type));
	    obstack_grow0 (&temporary_obstack,
			   IDENTIFIER_POINTER (t), IDENTIFIER_LENGTH (t));

	    sig = get_identifier ((char *) obstack_base (&temporary_obstack));
	    obstack_free (&temporary_obstack,
			  obstack_base (&temporary_obstack));
	  }
	  break;
	bad_type:
	default:
	  gcc_unreachable ();
	}
      TYPE_SIGNATURE (type) = sig;
    }
  return sig;
}

/* Save signature string SIG (an IDENTIFIER_NODE) in TYPE for future use. */

void
set_java_signature (tree type, tree sig)
{
  tree old_sig;
  while (TREE_CODE (type) == POINTER_TYPE)
    type = TREE_TYPE (type);
  MAYBE_CREATE_TYPE_TYPE_LANG_SPECIFIC (type);
  old_sig = TYPE_SIGNATURE (type);
  if (old_sig != NULL_TREE && old_sig != sig)
    abort ();
  TYPE_SIGNATURE (type) = sig;
#if 0 /* careful about METHOD_TYPE */
  if (IDENTIFIER_SIGNATURE_TYPE (sig) == NULL_TREE && TREE_PERMANENT (type))
    IDENTIFIER_SIGNATURE_TYPE (sig) = type;
#endif
}

/* Search in SEARCHED_CLASS and its superclasses for a method matching
   METHOD_NAME and signature METHOD_SIGNATURE.  This function will
   only search for methods declared in the class hierarchy; interfaces
   will not be considered.  Returns NULL_TREE if the method is not
   found.  */
tree
lookup_argument_method (tree searched_class, tree method_name,
			tree method_signature)
{
  return lookup_do (searched_class, 0,
		    method_name, method_signature, 
		    build_java_argument_signature);
}

/* Like lookup_argument_method, but lets the caller set any flags
   desired.  */
tree
lookup_argument_method_generic (tree searched_class, tree method_name,
				tree method_signature, int flags)
{
  return lookup_do (searched_class, flags,
		    method_name, method_signature, 
		    build_java_argument_signature);
}


/* Search in class SEARCHED_CLASS (and its superclasses) for a method
   matching METHOD_NAME and signature METHOD_SIGNATURE.  Return a
   FUNCTION_DECL on success, or NULL_TREE if none found.  (Contrast
   lookup_argument_method, which ignores return type.)  If
   SEARCHED_CLASS is an interface, search it too. */
tree
lookup_java_method (tree searched_class, tree method_name,
		    tree method_signature)
{
  return lookup_do (searched_class, SEARCH_INTERFACE, method_name, 
		    method_signature, build_java_signature);
}

/* Return true iff KLASS (or its ancestors) has a method METHOD_NAME.  */
int
has_method (tree klass, tree method_name)
{
  return lookup_do (klass, SEARCH_INTERFACE,
		    method_name, NULL_TREE,
		    build_null_signature) != NULL_TREE;
}

/* Search in class SEARCHED_CLASS, but not its superclasses, for a
   method matching METHOD_NAME and signature SIGNATURE.  A private
   helper for lookup_do.  */
static tree
shallow_find_method (tree searched_class, int flags, tree method_name, 
	     tree signature, tree (*signature_builder) (tree))
{
  tree method;
  for (method = TYPE_METHODS (searched_class);
       method != NULL_TREE;  method = DECL_CHAIN (method))
    {
      tree method_sig = (*signature_builder) (TREE_TYPE (method));
      if (DECL_NAME (method) == method_name && method_sig == signature)
	{
	  /* If the caller requires a visible method, then we
	     skip invisible methods here.  */
	  if (! (flags & SEARCH_VISIBLE)
	      || ! METHOD_INVISIBLE (method))
	    return method;
	}
    }
  return NULL_TREE;
}

/* Search in the superclasses of SEARCHED_CLASS for a method matching
   METHOD_NAME and signature SIGNATURE.  A private helper for
   lookup_do.  */
static tree
find_method_in_superclasses (tree searched_class, int flags, 
                             tree method_name, tree signature,
                             tree (*signature_builder) (tree))
{
  tree klass;
  for (klass = CLASSTYPE_SUPER (searched_class); klass != NULL_TREE;
       klass = CLASSTYPE_SUPER (klass))
    {
      tree method;
      method = shallow_find_method (klass, flags, method_name, 
				    signature, signature_builder);
      if (method != NULL_TREE)
	return method;
    }

  return NULL_TREE;
}

/* Search in the interfaces of SEARCHED_CLASS and its superinterfaces
   for a method matching METHOD_NAME and signature SIGNATURE.  A
   private helper for lookup_do.  */
static tree
find_method_in_interfaces (tree searched_class, int flags, tree method_name,
                           tree signature, tree (*signature_builder) (tree))
{
  int i;
  tree binfo, base_binfo;

  for (binfo = TYPE_BINFO (searched_class), i = 1;
       BINFO_BASE_ITERATE (binfo, i, base_binfo); i++)
    {
      tree iclass = BINFO_TYPE (base_binfo);
      tree method;
	  
      /* If the superinterface hasn't been loaded yet, do so now.  */
      if (!CLASS_LOADED_P (iclass))
	load_class (iclass, 1);
	  
      /* First, we look in ICLASS.  If that doesn't work we'll
	 recursively look through all its superinterfaces.  */
      method = shallow_find_method (iclass, flags, method_name, 
				    signature, signature_builder);      
      if (method != NULL_TREE)
	return method;
  
      method = find_method_in_interfaces 
	(iclass, flags, method_name, signature, signature_builder);
      if (method != NULL_TREE)
	return method;
    }
  
  return NULL_TREE;
}


/* Search in class SEARCHED_CLASS (and its superclasses) for a method
   matching METHOD_NAME and signature SIGNATURE.  FLAGS control some
   parameters of the search.
   
   SEARCH_INTERFACE means also search interfaces and superinterfaces
   of SEARCHED_CLASS.
   
   SEARCH_SUPER means skip SEARCHED_CLASS and start with its
   superclass.
   
   SEARCH_VISIBLE means skip methods for which METHOD_INVISIBLE is
   set.

   Return the matched method DECL or NULL_TREE.  SIGNATURE_BUILDER is
   used on method candidates to build their (sometimes partial)
   signature.  */
static tree
lookup_do (tree searched_class, int flags, tree method_name,
	   tree signature, tree (*signature_builder) (tree))
{
  tree method;
  tree orig_class = searched_class;
    
  if (searched_class == NULL_TREE)
    return NULL_TREE;

  if (flags & SEARCH_SUPER)
    {
      searched_class = CLASSTYPE_SUPER (searched_class);
      if (searched_class == NULL_TREE)
	return NULL_TREE;
    }

  /* First look in our own methods.  */
  method = shallow_find_method (searched_class, flags, method_name,
				signature, signature_builder);  
  if (method)
    return method;

  /* Then look in our superclasses.  */
  if (! CLASS_INTERFACE (TYPE_NAME (searched_class)))
    method = find_method_in_superclasses (searched_class, flags, method_name,
					  signature, signature_builder);  
  if (method)
    return method;
  
  /* If that doesn't work, look in our interfaces.  */
  if (flags & SEARCH_INTERFACE)
    method = find_method_in_interfaces (orig_class, flags, method_name, 
					signature, signature_builder);
  
  return method;
}

/* Search in class CLAS for a constructor matching METHOD_SIGNATURE.
   Return a FUNCTION_DECL on success, or NULL_TREE if none found. */

tree
lookup_java_constructor (tree clas, tree method_signature)
{
  tree method = TYPE_METHODS (clas);
  for ( ; method != NULL_TREE;  method = DECL_CHAIN (method))
    {
      tree method_sig = build_java_signature (TREE_TYPE (method));
      if (DECL_CONSTRUCTOR_P (method) && method_sig == method_signature)
	return method;
    }
  return NULL_TREE;
}

/* Return a type which is the Binary Numeric Promotion of the pair T1,
   T2 and convert EXP1 and/or EXP2. See 5.6.2 Binary Numeric
   Promotion. It assumes that both T1 and T2 are eligible to BNP. */

tree
binary_numeric_promotion (tree t1, tree t2, tree *exp1, tree *exp2)
{
  if (t1 == double_type_node || t2 == double_type_node)
    {
      if (t1 != double_type_node)
	*exp1 = convert (double_type_node, *exp1);
      if (t2 != double_type_node)
	*exp2 = convert (double_type_node, *exp2);
      return double_type_node;
    }
  if (t1 == float_type_node || t2 == float_type_node)
    {
      if (t1 != float_type_node)
	*exp1 = convert (float_type_node, *exp1);
      if (t2 != float_type_node)
	*exp2 = convert (float_type_node, *exp2);
      return float_type_node;
    }
  if (t1 == long_type_node || t2 == long_type_node)
    {
      if (t1 != long_type_node)
	*exp1 = convert (long_type_node, *exp1);
      if (t2 != long_type_node)
	*exp2 = convert (long_type_node, *exp2);
      return long_type_node;
    }

  if (t1 != int_type_node)
    *exp1 = convert (int_type_node, *exp1);
  if (t2 != int_type_node)
    *exp2 = convert (int_type_node, *exp2);
  return int_type_node;
}