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Block objects [1] are a C-level syntactic and runtime feature. They are similar to standard C functions, but in addition to executable code they may also contain variable bindings to automatic (stack) or managed (heap) memory. A block can therefore maintain a set of state (data) that it can use to impact behavior when executed. This port is based on Apple's GCC 5646 with some bugfixes from Apple GCC 5666.3. It has some small differences with the support in clang, which remains the recommended compiler. Perhaps the most notable difference is that in GCC that __block is not actually a keyword, but a macro. There will be workaround for this issue in a near future. Other issues can be consulted in the clang documentation [2] For better compatiblity with Apple's GCC and llvm-gcc some related fixes and features from Apple have been included. Support for the non-standard nested functions in GCC is now off by default. No effort was made to update the ObjC support since FreeBSD doesn't carry ObjC in the base system, but some of the code crept in and was more difficult to remove than to adjust. Reference: [1] https://developer.apple.com/library/mac/documentation/Cocoa/Conceptual/Blocks/Articles/00_Introduction.html [2] http://clang.llvm.org/compatibility.html#block-variable-initialization Obtained from: Apple GCC 4.2 MFC after: 3 weeks
124 lines
4.1 KiB
C
124 lines
4.1 KiB
C
/* Language-level data type conversion for GNU C.
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Copyright (C) 1987, 1988, 1991, 1998, 2002, 2003, 2004, 2005
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Free Software Foundation, Inc.
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This file is part of GCC.
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GCC is free software; you can redistribute it and/or modify it under
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the terms of the GNU General Public License as published by the Free
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Software Foundation; either version 2, or (at your option) any later
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version.
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GCC is distributed in the hope that it will be useful, but WITHOUT ANY
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WARRANTY; without even the implied warranty of MERCHANTABILITY or
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FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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for more details.
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You should have received a copy of the GNU General Public License
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along with GCC; see the file COPYING. If not, write to the Free
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Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
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02110-1301, USA. */
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/* This file contains the functions for converting C expressions
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to different data types. The only entry point is `convert'.
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Every language front end must have a `convert' function
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but what kind of conversions it does will depend on the language. */
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#include "config.h"
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#include "system.h"
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#include "coretypes.h"
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#include "tm.h"
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#include "tree.h"
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#include "flags.h"
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#include "convert.h"
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#include "c-common.h"
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#include "c-tree.h"
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#include "langhooks.h"
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#include "toplev.h"
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#include "target.h"
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/* Change of width--truncation and extension of integers or reals--
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is represented with NOP_EXPR. Proper functioning of many things
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assumes that no other conversions can be NOP_EXPRs.
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Conversion between integer and pointer is represented with CONVERT_EXPR.
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Converting integer to real uses FLOAT_EXPR
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and real to integer uses FIX_TRUNC_EXPR.
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Here is a list of all the functions that assume that widening and
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narrowing is always done with a NOP_EXPR:
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In convert.c, convert_to_integer.
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In c-typeck.c, build_binary_op (boolean ops), and
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c_common_truthvalue_conversion.
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In expr.c: expand_expr, for operands of a MULT_EXPR.
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In fold-const.c: fold.
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In tree.c: get_narrower and get_unwidened. */
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/* Subroutines of `convert'. */
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/* Create an expression whose value is that of EXPR,
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converted to type TYPE. The TREE_TYPE of the value
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is always TYPE. This function implements all reasonable
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conversions; callers should filter out those that are
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not permitted by the language being compiled. */
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tree
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convert (tree type, tree expr)
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{
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tree e = expr;
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enum tree_code code = TREE_CODE (type);
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const char *invalid_conv_diag;
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if (type == error_mark_node
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|| expr == error_mark_node
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|| TREE_TYPE (expr) == error_mark_node)
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return error_mark_node;
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if ((invalid_conv_diag
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= targetm.invalid_conversion (TREE_TYPE (expr), type)))
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{
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error (invalid_conv_diag, "");
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return error_mark_node;
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}
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if (type == TREE_TYPE (expr))
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return expr;
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if (TYPE_MAIN_VARIANT (type) == TYPE_MAIN_VARIANT (TREE_TYPE (expr)))
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return fold_convert (type, expr);
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if (TREE_CODE (TREE_TYPE (expr)) == ERROR_MARK)
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return error_mark_node;
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if (TREE_CODE (TREE_TYPE (expr)) == VOID_TYPE)
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{
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error ("void value not ignored as it ought to be");
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return error_mark_node;
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}
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if (code == VOID_TYPE)
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return fold_convert (type, e);
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if (code == INTEGER_TYPE || code == ENUMERAL_TYPE)
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return fold (convert_to_integer (type, e));
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if (code == BOOLEAN_TYPE)
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return fold_convert (type, c_objc_common_truthvalue_conversion (expr));
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if (code == POINTER_TYPE || code == REFERENCE_TYPE)
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return fold (convert_to_pointer (type, e));
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/* APPLE LOCAL begin blocks (C++ ck) */
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if (code == BLOCK_POINTER_TYPE)
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return fold (convert_to_block_pointer (type, e));
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/* APPLE LOCAL end blocks (C++ ck) */
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if (code == REAL_TYPE)
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return fold (convert_to_real (type, e));
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if (code == COMPLEX_TYPE)
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return fold (convert_to_complex (type, e));
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if (code == VECTOR_TYPE)
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return fold (convert_to_vector (type, e));
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if ((code == RECORD_TYPE || code == UNION_TYPE)
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&& lang_hooks.types_compatible_p (type, TREE_TYPE (expr)))
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return e;
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error ("conversion to non-scalar type requested");
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return error_mark_node;
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}
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