typeck.c

gcc-2.95.3 Linux下最常用的C编译器

/* Handle types for the GNU compiler for the Java(TM) language.
   Copyright (C) 1996, 97-98, 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.  

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 <[e-mail]> */

#include "config.h"
#include "system.h"
#include "tree.h"
#include "obstack.h"
#include "flags.h"
#include "java-tree.h"
#include "jcf.h"
#include "convert.h"
#include "toplev.h"

tree * type_map;
extern struct obstack permanent_obstack;

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

void
set_local_type (slot, type)
     int slot;
     tree type;
{
  int max_locals = DECL_MAX_LOCALS(current_function_decl);
  int nslots = TYPE_IS_WIDE (type) ? 2 : 1;
  if (slot < 0 || slot + nslots - 1 >= max_locals)
    fatal ("invalid local variable index");
  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.  This
   conversion produces something like:
   
   ({ double tmp = expr; (tmp != tmp) ? 0 : (int)tmp; })

   */

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

  return build (COND_EXPR, type, 
		build (NE_EXPR, boolean_type_node, expr, expr),
		convert (type, integer_zero_node),
		convert_to_integer (type, expr));
}  

/* 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 (type, expr)
     tree type, expr;
{
  register enum tree_code code = TREE_CODE (type);

  if (do_not_fold)
    return build1 (NOP_EXPR, type, expr);

  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_to_boolean (type, expr));
  if (code == INTEGER_TYPE)
    {
      if (TREE_CODE (TREE_TYPE (expr)) == REAL_TYPE
#ifdef TARGET_SOFT_FLOAT
	  && !TARGET_SOFT_FLOAT
#endif
	  && !flag_emit_class_files
	  && !flag_fast_math
	  && TARGET_FLOAT_FORMAT == IEEE_FLOAT_FORMAT)
	return fold (convert_ieee_real_to_integer (type, expr));
      else
	return fold (convert_to_integer (type, expr));
    }	  
  if (code == REAL_TYPE)
    return fold (convert_to_real (type, expr));
  if (code == CHAR_TYPE)
    return fold (convert_to_char (type, expr));
  if (code == POINTER_TYPE)
    return fold (convert_to_pointer (type, expr));
  error ("conversion to non-scalar type requested");
  return error_mark_node;
}


tree
convert_to_char (type, expr)
    tree type, expr;
{
  return build1 (NOP_EXPR, type, expr);
}

tree
convert_to_boolean (type, expr)
     tree type, expr;
{
  return build1 (NOP_EXPR, type, expr);
}

/* Print an error message for invalid use of an incomplete type.
   VALUE is the expression that was used (or 0 if that isn't known)
   and TYPE is the type that was invalid.  */

void
incomplete_type_error (value, type)
  tree value ATTRIBUTE_UNUSED;
  tree type ATTRIBUTE_UNUSED;
{
  error ("internal error - use of undefined type");
}

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

tree
type_for_mode (mode, unsignedp)
     enum 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
type_for_size (bits, unsignedp)
     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;
}

/* Return a type the same as TYPE except unsigned or
   signed according to UNSIGNEDP.  */

tree
signed_or_unsigned_type (unsignedp, type)
     int unsignedp;
     tree type;
{
  if (! INTEGRAL_TYPE_P (type))
    return type;
  if (TYPE_PRECISION (type) == TYPE_PRECISION (int_type_node))
    return unsignedp ? unsigned_int_type_node : int_type_node;
  if (TYPE_PRECISION (type) == TYPE_PRECISION (byte_type_node))
    return unsignedp ? unsigned_byte_type_node : byte_type_node;
  if (TYPE_PRECISION (type) == TYPE_PRECISION (short_type_node))
    return unsignedp ? unsigned_short_type_node : short_type_node;
  if (TYPE_PRECISION (type) == TYPE_PRECISION (long_type_node))
    return unsignedp ? unsigned_long_type_node : long_type_node;
  return type;
}

/* Return a signed type the same as TYPE in other respects.  */

tree
signed_type (type)
     tree type;
{
  return signed_or_unsigned_type (0, type);
}

/* Return an unsigned type the same as TYPE in other respects.  */

tree
unsigned_type (type)
     tree type;
{
  return signed_or_unsigned_type (1, type);

}

/* Mark EXP saying that we need to be able to take the
   address of it; it should not be allocated in a register.
   Value is 1 if successful.  */

int
mark_addressable (exp)
     tree exp;
{
  register tree x = exp;
  while (1)
    switch (TREE_CODE (x))
      {
      case ADDR_EXPR:
      case COMPONENT_REF:
      case ARRAY_REF:
      case REALPART_EXPR:
      case IMAGPART_EXPR:
	x = TREE_OPERAND (x, 0);
	break;

      case TRUTH_ANDIF_EXPR:
      case TRUTH_ORIF_EXPR:
      case COMPOUND_EXPR:
	x = TREE_OPERAND (x, 1);
	break;

      case COND_EXPR:
	return mark_addressable (TREE_OPERAND (x, 1))
	  & mark_addressable (TREE_OPERAND (x, 2));

      case CONSTRUCTOR:
	TREE_ADDRESSABLE (x) = 1;
	return 1;

      case INDIRECT_REF:
	/* We sometimes add a cast *(TYPE*)&FOO to handle type and mode
	   incompatibility problems.  Handle this case by marking FOO.  */
	if (TREE_CODE (TREE_OPERAND (x, 0)) == NOP_EXPR
	    && TREE_CODE (TREE_OPERAND (TREE_OPERAND (x, 0), 0)) == ADDR_EXPR)
	  {
	    x = TREE_OPERAND (TREE_OPERAND (x, 0), 0);
	    break;
	  }
	if (TREE_CODE (TREE_OPERAND (x, 0)) == ADDR_EXPR)
	  {
	    x = TREE_OPERAND (x, 0);
	    break;
	  }
	return 1;

      case VAR_DECL:
      case CONST_DECL:
      case PARM_DECL:
      case RESULT_DECL:
      case FUNCTION_DECL:
	TREE_ADDRESSABLE (x) = 1;
#if 0  /* poplevel deals with this now.  */
	if (DECL_CONTEXT (x) == 0)
	  TREE_ADDRESSABLE (DECL_ASSEMBLER_NAME (x)) = 1;
#endif
	/* drops through */
      default:
	return 1;
    }
}

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

int
is_array_type_p (type)
     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 (array_type)
     tree array_type;
{
  tree arfld;
  if (TREE_CODE (array_type) == POINTER_TYPE)
    array_type = TREE_TYPE (array_type);
  arfld = TREE_CHAIN (TREE_CHAIN (TYPE_FIELDS (array_type)));
  if (arfld != NULL_TREE)
    {
      tree index_type = TYPE_DOMAIN (TREE_TYPE (arfld));
      tree high = TYPE_MAX_VALUE (index_type);
      if (TREE_CODE (high) == INTEGER_CST)
	return TREE_INT_CST_LOW (high) + 1;
    }
  return -1;
}

tree
build_prim_array_type (element_type, length)
     tree element_type;
     HOST_WIDE_INT length;
{
  tree max_index = build_int_2 (length - 1, 0);
  TREE_TYPE (max_index) = sizetype;
  return build_array_type (element_type, build_index_type (max_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 (element_type, length)
     tree element_type;
     HOST_WIDE_INT length;
{
  tree sig, t, fld;
  char buf[12];
  tree elsig = build_java_signature (element_type);
  tree el_name = element_type;
  sprintf (buf, length >= 0 ? "[%d" : "[", length);
  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);
  TYPE_NAME (t) = identifier_subst (el_name, "", '.', '.', "[]");

  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. */
  push_obstacks (&permanent_obstack, &permanent_obstack);
  fld = build_decl (FIELD_DECL, get_identifier ("length"), int_type_node);
  TYPE_FIELDS (t) = fld;
  DECL_CONTEXT (fld) = t;
  FIELD_PUBLIC (fld) = 1;
  FIELD_FINAL (fld) = 1;

  if (length >= 0)
    {
      tree atype = build_prim_array_type (element_type, length);
      tree arfld = build_decl (FIELD_DECL, get_identifier ("data"), atype);
      DECL_CONTEXT (arfld) = t;
      TREE_CHAIN (fld) = arfld;
    }
  else
    TYPE_ALIGN (t) = TYPE_ALIGN (element_type);
  pop_obstacks ();

  /* 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. */