| /* Language-level data type conversion for GNU C. |
| Copyright (C) 1987-2019 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/>. */ |
| |
| |
| /* This file contains the functions for converting C expressions |
| to different data types. The only entry point is `convert'. |
| Every language front end must have a `convert' function |
| but what kind of conversions it does will depend on the language. */ |
| |
| #include "config.h" |
| #include "system.h" |
| #include "coretypes.h" |
| #include "target.h" |
| #include "c-tree.h" |
| #include "convert.h" |
| #include "langhooks.h" |
| #include "ubsan.h" |
| #include "stringpool.h" |
| #include "attribs.h" |
| #include "asan.h" |
| |
| /* Change of width--truncation and extension of integers or reals-- |
| is represented with NOP_EXPR. Proper functioning of many things |
| assumes that no other conversions can be NOP_EXPRs. |
| |
| Conversion between integer and pointer is represented with CONVERT_EXPR. |
| Converting integer to real uses FLOAT_EXPR |
| and real to integer uses FIX_TRUNC_EXPR. |
| |
| Here is a list of all the functions that assume that widening and |
| narrowing is always done with a NOP_EXPR: |
| In convert.c, convert_to_integer. |
| In c-typeck.c, build_binary_op (boolean ops), and |
| c_common_truthvalue_conversion. |
| In expr.c: expand_expr, for operands of a MULT_EXPR. |
| In fold-const.c: fold. |
| In tree.c: get_narrower and get_unwidened. */ |
| |
| /* Subroutines of `convert'. */ |
| |
| |
| |
| /* 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) |
| { |
| tree e = expr; |
| enum tree_code code = TREE_CODE (type); |
| const char *invalid_conv_diag; |
| tree ret; |
| location_t loc = EXPR_LOCATION (expr); |
| |
| if (type == error_mark_node |
| || error_operand_p (expr)) |
| return error_mark_node; |
| |
| if ((invalid_conv_diag |
| = targetm.invalid_conversion (TREE_TYPE (expr), type))) |
| { |
| error (invalid_conv_diag); |
| return error_mark_node; |
| } |
| |
| if (type == TREE_TYPE (expr)) |
| return expr; |
| ret = targetm.convert_to_type (type, expr); |
| if (ret) |
| return ret; |
| |
| STRIP_TYPE_NOPS (e); |
| |
| if (TYPE_MAIN_VARIANT (type) == TYPE_MAIN_VARIANT (TREE_TYPE (expr)) |
| && (TREE_CODE (TREE_TYPE (expr)) != COMPLEX_TYPE |
| || TREE_CODE (e) == COMPLEX_EXPR)) |
| return fold_convert_loc (loc, type, expr); |
| if (TREE_CODE (TREE_TYPE (expr)) == ERROR_MARK) |
| return error_mark_node; |
| if (TREE_CODE (TREE_TYPE (expr)) == VOID_TYPE) |
| { |
| error ("void value not ignored as it ought to be"); |
| return error_mark_node; |
| } |
| |
| switch (code) |
| { |
| case VOID_TYPE: |
| return fold_convert_loc (loc, type, e); |
| |
| case INTEGER_TYPE: |
| case ENUMERAL_TYPE: |
| if (sanitize_flags_p (SANITIZE_FLOAT_CAST) |
| && current_function_decl != NULL_TREE |
| && TREE_CODE (TREE_TYPE (expr)) == REAL_TYPE |
| && COMPLETE_TYPE_P (type)) |
| { |
| expr = save_expr (expr); |
| expr = c_fully_fold (expr, false, NULL); |
| tree check = ubsan_instrument_float_cast (loc, type, expr); |
| expr = fold_build1 (FIX_TRUNC_EXPR, type, expr); |
| if (check == NULL_TREE) |
| return expr; |
| return fold_build2 (COMPOUND_EXPR, TREE_TYPE (expr), check, expr); |
| } |
| ret = convert_to_integer (type, e); |
| goto maybe_fold; |
| |
| case BOOLEAN_TYPE: |
| return fold_convert_loc |
| (loc, type, c_objc_common_truthvalue_conversion (input_location, expr)); |
| |
| case POINTER_TYPE: |
| case REFERENCE_TYPE: |
| ret = convert_to_pointer (type, e); |
| goto maybe_fold; |
| |
| case REAL_TYPE: |
| ret = convert_to_real (type, e); |
| goto maybe_fold; |
| |
| case FIXED_POINT_TYPE: |
| ret = convert_to_fixed (type, e); |
| goto maybe_fold; |
| |
| case COMPLEX_TYPE: |
| ret = convert_to_complex (type, e); |
| goto maybe_fold; |
| |
| case VECTOR_TYPE: |
| ret = convert_to_vector (type, e); |
| goto maybe_fold; |
| |
| case RECORD_TYPE: |
| case UNION_TYPE: |
| if (lang_hooks.types_compatible_p (type, TREE_TYPE (expr))) |
| return e; |
| break; |
| |
| default: |
| break; |
| |
| maybe_fold: |
| if (TREE_CODE (ret) != C_MAYBE_CONST_EXPR) |
| ret = fold (ret); |
| return ret; |
| } |
| |
| error ("conversion to non-scalar type requested"); |
| return error_mark_node; |
| } |