sdcc/support/cpp/gcc/c/c-convert.cc

   1 /* Language-level data type conversion for GNU C.
   2    Copyright (C) 1987-2022 Free Software Foundation, Inc.
   3
   4 This file is part of GCC.
   5
   6 GCC is free software; you can redistribute it and/or modify it under
   7 the terms of the GNU General Public License as published by the Free
   8 Software Foundation; either version 3, or (at your option) any later
   9 version.
  10
  11 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  12 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14 for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with GCC; see the file COPYING3.  If not see
  18 <http://www.gnu.org/licenses/>.  */
  19
  20
  21 /* This file contains the functions for converting C expressions
  22    to different data types.  The only entry point is `convert'.
  23    Every language front end must have a `convert' function
  24    but what kind of conversions it does will depend on the language.  */
  25
  26 #include "config.h"
  27 #include "system.h"
  28 #include "coretypes.h"
  29 #include "target.h"
  30 #include "c-tree.h"
  31 #include "convert.h"
  32 #include "langhooks.h"
  33 // #include "ubsan.h"
  34 #include "stringpool.h"
  35 #include "attribs.h"
  36 #include "asan.h"
  37
  38 /* Change of width--truncation and extension of integers or reals--
  39    is represented with NOP_EXPR.  Proper functioning of many things
  40    assumes that no other conversions can be NOP_EXPRs.
  41
  42    Conversion between integer and pointer is represented with CONVERT_EXPR.
  43    Converting integer to real uses FLOAT_EXPR
  44    and real to integer uses FIX_TRUNC_EXPR.
  45
  46    Here is a list of all the functions that assume that widening and
  47    narrowing is always done with a NOP_EXPR:
  48      In convert.cc, convert_to_integer.
  49      In c-typeck.cc, build_binary_op (boolean ops), and
  50         c_common_truthvalue_conversion.
  51      In expr.cc: expand_expr, for operands of a MULT_EXPR.
  52      In fold-const.cc: fold.
  53      In tree.cc: get_narrower and get_unwidened.  */
  54 \f
  55 /* Subroutines of `convert'.  */
  56
  57
  58 \f
  59 /* Create an expression whose value is that of EXPR,
  60    converted to type TYPE.  The TREE_TYPE of the value
  61    is always TYPE.  This function implements all reasonable
  62    conversions; callers should filter out those that are
  63    not permitted by the language being compiled.
  64    INIT_CONST is true if the conversion is for arithmetic types for a static
  65    initializer and folding must apply accordingly (discarding floating-point
  66    exceptions and assuming the default rounding mode is in effect).  */
  67
  68 static tree
  69 c_convert (tree type, tree expr, bool init_const)
  70 {
  71         (void) type;
  72         (void) expr;
  73         (void) init_const;
  74         gcc_assert(0);
  75         return tree();
  76 #if 0 // sdcpp
  77   tree e = expr;
  78   enum tree_code code = TREE_CODE (type);
  79   const char *invalid_conv_diag;
  80   tree ret;
  81   location_t loc = EXPR_LOCATION (expr);
  82
  83   if (type == error_mark_node
  84       || error_operand_p (expr))
  85     return error_mark_node;
  86
  87   if ((invalid_conv_diag
  88        = targetm.invalid_conversion (TREE_TYPE (expr), type)))
  89     {
  90       error (invalid_conv_diag);
  91       return error_mark_node;
  92     }
  93
  94   if (type == TREE_TYPE (expr))
  95     return expr;
  96   ret = targetm.convert_to_type (type, expr);
  97   if (ret)
  98       return ret;
  99
 100   STRIP_TYPE_NOPS (e);
 101
 102   if (TYPE_MAIN_VARIANT (type) == TYPE_MAIN_VARIANT (TREE_TYPE (expr))
 103       && (TREE_CODE (TREE_TYPE (expr)) != COMPLEX_TYPE
 104           || TREE_CODE (e) == COMPLEX_EXPR))
 105     return fold_convert_loc (loc, type, expr);
 106   if (TREE_CODE (TREE_TYPE (expr)) == ERROR_MARK)
 107     return error_mark_node;
 108   if (TREE_CODE (TREE_TYPE (expr)) == VOID_TYPE)
 109     {
 110       error ("void value not ignored as it ought to be");
 111       return error_mark_node;
 112     }
 113
 114   switch (code)
 115     {
 116     case VOID_TYPE:
 117       return fold_convert_loc (loc, type, e);
 118
 119     case INTEGER_TYPE:
 120     case ENUMERAL_TYPE:
 121       if (sanitize_flags_p (SANITIZE_FLOAT_CAST)
 122           && current_function_decl != NULL_TREE
 123           && TREE_CODE (TREE_TYPE (expr)) == REAL_TYPE
 124           && COMPLETE_TYPE_P (type))
 125         {
 126           expr = save_expr (expr);
 127           expr = c_fully_fold (expr, init_const, NULL);
 128           tree check = ubsan_instrument_float_cast (loc, type, expr);
 129           expr = fold_build1 (FIX_TRUNC_EXPR, type, expr);
 130           if (check == NULL_TREE)
 131             return expr;
 132           return fold_build2 (COMPOUND_EXPR, TREE_TYPE (expr), check, expr);
 133         }
 134       ret = convert_to_integer (type, e);
 135       goto maybe_fold;
 136
 137     case BOOLEAN_TYPE:
 138       return fold_convert_loc
 139         (loc, type, c_objc_common_truthvalue_conversion (input_location, expr));
 140
 141     case POINTER_TYPE:
 142     case REFERENCE_TYPE:
 143       ret = convert_to_pointer (type, e);
 144       goto maybe_fold;
 145
 146     case REAL_TYPE:
 147       ret = convert_to_real (type, e);
 148       goto maybe_fold;
 149
 150     case FIXED_POINT_TYPE:
 151       ret = convert_to_fixed (type, e);
 152       goto maybe_fold;
 153
 154     case COMPLEX_TYPE:
 155       ret = convert_to_complex (type, e);
 156       goto maybe_fold;
 157
 158     case VECTOR_TYPE:
 159       if (gnu_vector_type_p (type)
 160           || gnu_vector_type_p (TREE_TYPE (e))
 161           /* Allow conversions between compatible non-GNU vector types
 162              when -flax-vector-conversions is passed.  The whole purpose
 163              of the option is to bend the normal type rules and accept
 164              nonconforming code.  */
 165           || (flag_lax_vector_conversions
 166               && VECTOR_TYPE_P (TREE_TYPE (e))
 167               && vector_types_convertible_p (type, TREE_TYPE (e), false)))
 168         {
 169           ret = convert_to_vector (type, e);
 170           goto maybe_fold;
 171         }
 172       break;
 173
 174     case RECORD_TYPE:
 175     case UNION_TYPE:
 176       if (lang_hooks.types_compatible_p (type, TREE_TYPE (expr)))
 177         return e;
 178       break;
 179
 180     default:
 181       break;
 182
 183     maybe_fold:
 184       if (TREE_CODE (ret) != C_MAYBE_CONST_EXPR)
 185         ret = init_const ? fold_init (ret) : fold (ret);
 186       return ret;
 187     }
 188
 189   error ("conversion to non-scalar type requested");
 190   return error_mark_node;
 191 #endif
 192 }
 193
 194 /* Create an expression whose value is that of EXPR, converted to type TYPE.
 195    The TREE_TYPE of the value is always TYPE.  This function implements all
 196    reasonable conversions; callers should filter out those that are not
 197    permitted by the language being compiled.  */
 198
 199 tree
 200 convert (tree type, tree expr)
 201 {
 202   return c_convert (type, expr, false);
 203 }
 204
 205 /* Create an expression whose value is that of EXPR, converted to type TYPE, in
 206    a static initializer.  The TREE_TYPE of the value is always TYPE.  This
 207    function implements all reasonable conversions; callers should filter out
 208    those that are not permitted by the language being compiled.  */
 209
 210 tree
 211 convert_init (tree type, tree expr)
 212 {
 213   return c_convert (type, expr, true);
 214 }