[8833] | 1 | /* C-compiler utilities for types and variables storage layout |
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| 2 | Copyright (C) 1987, 88, 92, 93, 94, 1995 Free Software Foundation, Inc. |
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| 3 | |
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| 4 | This file is part of GNU CC. |
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| 5 | |
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| 6 | GNU CC is free software; you can redistribute it and/or modify |
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| 7 | it under the terms of the GNU General Public License as published by |
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| 8 | the Free Software Foundation; either version 2, or (at your option) |
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| 9 | any later version. |
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| 10 | |
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| 11 | GNU CC is distributed in the hope that it will be useful, |
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| 12 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
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| 13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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| 14 | GNU General Public License for more details. |
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| 15 | |
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| 16 | You should have received a copy of the GNU General Public License |
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| 17 | along with GNU CC; see the file COPYING. If not, write to |
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| 18 | the Free Software Foundation, 59 Temple Place - Suite 330, |
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| 19 | Boston, MA 02111-1307, USA. */ |
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| 20 | |
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| 21 | |
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| 22 | #include "config.h" |
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| 23 | #include <stdio.h> |
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| 24 | |
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| 25 | #include "tree.h" |
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| 26 | #include "flags.h" |
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| 27 | #include "function.h" |
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| 28 | |
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| 29 | #define CEIL(x,y) (((x) + (y) - 1) / (y)) |
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| 30 | |
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| 31 | /* Data type for the expressions representing sizes of data types. |
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| 32 | It is the first integer type laid out. |
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| 33 | In C, this is int. */ |
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| 34 | |
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| 35 | tree sizetype; |
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| 36 | |
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| 37 | /* An integer constant with value 0 whose type is sizetype. */ |
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| 38 | |
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| 39 | tree size_zero_node; |
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| 40 | |
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| 41 | /* An integer constant with value 1 whose type is sizetype. */ |
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| 42 | |
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| 43 | tree size_one_node; |
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| 44 | |
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| 45 | /* If nonzero, this is an upper limit on alignment of structure fields. |
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| 46 | The value is measured in bits. */ |
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| 47 | int maximum_field_alignment; |
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| 48 | |
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| 49 | /* If non-zero, the alignment of a bitstring or (power-)set value, in bits. |
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| 50 | May be overridden by front-ends. */ |
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| 51 | int set_alignment = 0; |
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| 52 | |
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| 53 | #define GET_MODE_ALIGNMENT(MODE) \ |
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| 54 | MIN (BIGGEST_ALIGNMENT, \ |
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| 55 | MAX (1, (GET_MODE_UNIT_SIZE (MODE) * BITS_PER_UNIT))) |
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| 56 | |
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| 57 | static enum machine_mode smallest_mode_for_size PROTO((unsigned int, |
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| 58 | enum mode_class)); |
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| 59 | static tree layout_record PROTO((tree)); |
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| 60 | static void layout_union PROTO((tree)); |
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| 61 | |
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| 62 | /* SAVE_EXPRs for sizes of types and decls, waiting to be expanded. */ |
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| 63 | |
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| 64 | static tree pending_sizes; |
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| 65 | |
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| 66 | /* Nonzero means cannot safely call expand_expr now, |
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| 67 | so put variable sizes onto `pending_sizes' instead. */ |
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| 68 | |
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| 69 | int immediate_size_expand; |
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| 70 | |
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| 71 | tree |
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| 72 | get_pending_sizes () |
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| 73 | { |
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| 74 | tree chain = pending_sizes; |
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| 75 | tree t; |
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| 76 | |
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| 77 | /* Put each SAVE_EXPR into the current function. */ |
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| 78 | for (t = chain; t; t = TREE_CHAIN (t)) |
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| 79 | SAVE_EXPR_CONTEXT (TREE_VALUE (t)) = current_function_decl; |
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| 80 | pending_sizes = 0; |
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| 81 | return chain; |
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| 82 | } |
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| 83 | |
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| 84 | void |
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| 85 | put_pending_sizes (chain) |
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| 86 | tree chain; |
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| 87 | { |
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| 88 | if (pending_sizes) |
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| 89 | abort (); |
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| 90 | |
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| 91 | pending_sizes = chain; |
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| 92 | } |
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| 93 | |
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| 94 | /* Given a size SIZE that may not be a constant, return a SAVE_EXPR |
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| 95 | to serve as the actual size-expression for a type or decl. */ |
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| 96 | |
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| 97 | tree |
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| 98 | variable_size (size) |
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| 99 | tree size; |
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| 100 | { |
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| 101 | /* If the language-processor is to take responsibility for variable-sized |
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| 102 | items (e.g., languages which have elaboration procedures like Ada), |
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| 103 | just return SIZE unchanged. Likewise for self-referential sizes. */ |
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| 104 | if (TREE_CONSTANT (size) |
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| 105 | || global_bindings_p () < 0 || contains_placeholder_p (size)) |
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| 106 | return size; |
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| 107 | |
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| 108 | size = save_expr (size); |
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| 109 | |
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| 110 | if (global_bindings_p ()) |
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| 111 | { |
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| 112 | if (TREE_CONSTANT (size)) |
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| 113 | error ("type size can't be explicitly evaluated"); |
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| 114 | else |
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| 115 | error ("variable-size type declared outside of any function"); |
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| 116 | |
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| 117 | return size_int (1); |
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| 118 | } |
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| 119 | |
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| 120 | if (immediate_size_expand) |
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| 121 | /* NULL_RTX is not defined; neither is the rtx type. |
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| 122 | Also, we would like to pass const0_rtx here, but don't have it. */ |
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| 123 | expand_expr (size, expand_expr (integer_zero_node, NULL_PTR, VOIDmode, 0), |
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| 124 | VOIDmode, 0); |
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| 125 | else |
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| 126 | pending_sizes = tree_cons (NULL_TREE, size, pending_sizes); |
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| 127 | |
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| 128 | return size; |
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| 129 | } |
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| 130 | |
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| 131 | #ifndef MAX_FIXED_MODE_SIZE |
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| 132 | #define MAX_FIXED_MODE_SIZE GET_MODE_BITSIZE (DImode) |
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| 133 | #endif |
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| 134 | |
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| 135 | /* Return the machine mode to use for a nonscalar of SIZE bits. |
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| 136 | The mode must be in class CLASS, and have exactly that many bits. |
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| 137 | If LIMIT is nonzero, modes of wider than MAX_FIXED_MODE_SIZE will not |
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| 138 | be used. */ |
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| 139 | |
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| 140 | enum machine_mode |
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| 141 | mode_for_size (size, class, limit) |
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| 142 | unsigned int size; |
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| 143 | enum mode_class class; |
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| 144 | int limit; |
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| 145 | { |
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| 146 | register enum machine_mode mode; |
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| 147 | |
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| 148 | if (limit && size > MAX_FIXED_MODE_SIZE) |
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| 149 | return BLKmode; |
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| 150 | |
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| 151 | /* Get the first mode which has this size, in the specified class. */ |
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| 152 | for (mode = GET_CLASS_NARROWEST_MODE (class); mode != VOIDmode; |
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| 153 | mode = GET_MODE_WIDER_MODE (mode)) |
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| 154 | if (GET_MODE_BITSIZE (mode) == size) |
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| 155 | return mode; |
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| 156 | |
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| 157 | return BLKmode; |
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| 158 | } |
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| 159 | |
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| 160 | /* Similar, but never return BLKmode; return the narrowest mode that |
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| 161 | contains at least the requested number of bits. */ |
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| 162 | |
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| 163 | static enum machine_mode |
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| 164 | smallest_mode_for_size (size, class) |
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| 165 | unsigned int size; |
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| 166 | enum mode_class class; |
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| 167 | { |
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| 168 | register enum machine_mode mode; |
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| 169 | |
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| 170 | /* Get the first mode which has at least this size, in the |
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| 171 | specified class. */ |
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| 172 | for (mode = GET_CLASS_NARROWEST_MODE (class); mode != VOIDmode; |
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| 173 | mode = GET_MODE_WIDER_MODE (mode)) |
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| 174 | if (GET_MODE_BITSIZE (mode) >= size) |
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| 175 | return mode; |
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| 176 | |
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| 177 | abort (); |
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| 178 | } |
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| 179 | |
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| 180 | /* Return the value of VALUE, rounded up to a multiple of DIVISOR. */ |
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| 181 | |
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| 182 | tree |
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| 183 | round_up (value, divisor) |
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| 184 | tree value; |
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| 185 | int divisor; |
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| 186 | { |
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| 187 | return size_binop (MULT_EXPR, |
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| 188 | size_binop (CEIL_DIV_EXPR, value, size_int (divisor)), |
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| 189 | size_int (divisor)); |
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| 190 | } |
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| 191 | |
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| 192 | /* Set the size, mode and alignment of a ..._DECL node. |
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| 193 | TYPE_DECL does need this for C++. |
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| 194 | Note that LABEL_DECL and CONST_DECL nodes do not need this, |
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| 195 | and FUNCTION_DECL nodes have them set up in a special (and simple) way. |
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| 196 | Don't call layout_decl for them. |
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| 197 | |
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| 198 | KNOWN_ALIGN is the amount of alignment we can assume this |
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| 199 | decl has with no special effort. It is relevant only for FIELD_DECLs |
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| 200 | and depends on the previous fields. |
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| 201 | All that matters about KNOWN_ALIGN is which powers of 2 divide it. |
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| 202 | If KNOWN_ALIGN is 0, it means, "as much alignment as you like": |
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| 203 | the record will be aligned to suit. */ |
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| 204 | |
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| 205 | void |
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| 206 | layout_decl (decl, known_align) |
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| 207 | tree decl; |
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| 208 | unsigned known_align; |
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| 209 | { |
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| 210 | register tree type = TREE_TYPE (decl); |
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| 211 | register enum tree_code code = TREE_CODE (decl); |
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| 212 | int spec_size = DECL_FIELD_SIZE (decl); |
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| 213 | |
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| 214 | if (code == CONST_DECL) |
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| 215 | return; |
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| 216 | |
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| 217 | if (code != VAR_DECL && code != PARM_DECL && code != RESULT_DECL |
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| 218 | && code != FIELD_DECL && code != TYPE_DECL) |
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| 219 | abort (); |
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| 220 | |
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| 221 | if (type == error_mark_node) |
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| 222 | { |
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| 223 | type = void_type_node; |
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| 224 | spec_size = 0; |
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| 225 | } |
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| 226 | |
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| 227 | /* Usually the size and mode come from the data type without change. */ |
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| 228 | |
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| 229 | DECL_MODE (decl) = TYPE_MODE (type); |
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| 230 | TREE_UNSIGNED (decl) = TREE_UNSIGNED (type); |
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| 231 | if (DECL_SIZE (decl) == 0) |
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| 232 | DECL_SIZE (decl) = TYPE_SIZE (type); |
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| 233 | |
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| 234 | if (code == FIELD_DECL && DECL_BIT_FIELD (decl)) |
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| 235 | { |
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| 236 | if (spec_size == 0 && DECL_NAME (decl) != 0) |
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| 237 | abort (); |
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| 238 | |
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| 239 | /* Size is specified number of bits. */ |
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| 240 | DECL_SIZE (decl) = size_int (spec_size); |
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| 241 | } |
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| 242 | /* Force alignment required for the data type. |
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| 243 | But if the decl itself wants greater alignment, don't override that. |
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| 244 | Likewise, if the decl is packed, don't override it. */ |
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| 245 | else if (DECL_ALIGN (decl) == 0 |
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| 246 | || (! DECL_PACKED (decl) && TYPE_ALIGN (type) > DECL_ALIGN (decl))) |
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| 247 | DECL_ALIGN (decl) = TYPE_ALIGN (type); |
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| 248 | |
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| 249 | /* See if we can use an ordinary integer mode for a bit-field. */ |
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| 250 | /* Conditions are: a fixed size that is correct for another mode |
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| 251 | and occupying a complete byte or bytes on proper boundary. */ |
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| 252 | if (code == FIELD_DECL) |
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| 253 | { |
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| 254 | DECL_BIT_FIELD_TYPE (decl) = DECL_BIT_FIELD (decl) ? type : 0; |
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| 255 | if (maximum_field_alignment != 0) |
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| 256 | DECL_ALIGN (decl) = MIN (DECL_ALIGN (decl), maximum_field_alignment); |
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| 257 | else if (flag_pack_struct) |
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| 258 | DECL_ALIGN (decl) = MIN (DECL_ALIGN (decl), BITS_PER_UNIT); |
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| 259 | } |
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| 260 | |
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| 261 | if (DECL_BIT_FIELD (decl) |
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| 262 | && TYPE_SIZE (type) != 0 |
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| 263 | && TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST) |
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| 264 | { |
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| 265 | register enum machine_mode xmode |
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| 266 | = mode_for_size (TREE_INT_CST_LOW (DECL_SIZE (decl)), MODE_INT, 1); |
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| 267 | |
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| 268 | if (xmode != BLKmode |
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| 269 | && known_align % GET_MODE_ALIGNMENT (xmode) == 0) |
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| 270 | { |
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| 271 | DECL_ALIGN (decl) = MAX (GET_MODE_ALIGNMENT (xmode), |
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| 272 | DECL_ALIGN (decl)); |
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| 273 | DECL_MODE (decl) = xmode; |
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| 274 | DECL_SIZE (decl) = size_int (GET_MODE_BITSIZE (xmode)); |
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| 275 | /* This no longer needs to be accessed as a bit field. */ |
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| 276 | DECL_BIT_FIELD (decl) = 0; |
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| 277 | } |
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| 278 | } |
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| 279 | |
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| 280 | /* Evaluate nonconstant size only once, either now or as soon as safe. */ |
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| 281 | if (DECL_SIZE (decl) != 0 && TREE_CODE (DECL_SIZE (decl)) != INTEGER_CST) |
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| 282 | DECL_SIZE (decl) = variable_size (DECL_SIZE (decl)); |
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| 283 | } |
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| 284 | |
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| 285 | /* Lay out a RECORD_TYPE type (a C struct). |
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| 286 | This means laying out the fields, determining their positions, |
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| 287 | and computing the overall size and required alignment of the record. |
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| 288 | Note that if you set the TYPE_ALIGN before calling this |
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| 289 | then the struct is aligned to at least that boundary. |
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| 290 | |
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| 291 | If the type has basetypes, you must call layout_basetypes |
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| 292 | before calling this function. |
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| 293 | |
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| 294 | The return value is a list of static members of the record. |
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| 295 | They still need to be laid out. */ |
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| 296 | |
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| 297 | static tree |
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| 298 | layout_record (rec) |
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| 299 | tree rec; |
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| 300 | { |
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| 301 | register tree field; |
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| 302 | #ifdef STRUCTURE_SIZE_BOUNDARY |
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| 303 | unsigned record_align = MAX (STRUCTURE_SIZE_BOUNDARY, TYPE_ALIGN (rec)); |
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| 304 | #else |
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| 305 | unsigned record_align = MAX (BITS_PER_UNIT, TYPE_ALIGN (rec)); |
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| 306 | #endif |
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| 307 | /* These must be laid out *after* the record is. */ |
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| 308 | tree pending_statics = NULL_TREE; |
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| 309 | /* Record size so far is CONST_SIZE + VAR_SIZE bits, |
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| 310 | where CONST_SIZE is an integer |
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| 311 | and VAR_SIZE is a tree expression. |
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| 312 | If VAR_SIZE is null, the size is just CONST_SIZE. |
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| 313 | Naturally we try to avoid using VAR_SIZE. */ |
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| 314 | register int const_size = 0; |
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| 315 | register tree var_size = 0; |
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| 316 | /* Once we start using VAR_SIZE, this is the maximum alignment |
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| 317 | that we know VAR_SIZE has. */ |
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| 318 | register int var_align = BITS_PER_UNIT; |
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| 319 | |
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| 320 | |
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| 321 | for (field = TYPE_FIELDS (rec); field; field = TREE_CHAIN (field)) |
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| 322 | { |
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| 323 | register int known_align = var_size ? var_align : const_size; |
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| 324 | register int desired_align; |
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| 325 | |
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| 326 | /* If FIELD is static, then treat it like a separate variable, |
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| 327 | not really like a structure field. |
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| 328 | If it is a FUNCTION_DECL, it's a method. |
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| 329 | In both cases, all we do is lay out the decl, |
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| 330 | and we do it *after* the record is laid out. */ |
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| 331 | |
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| 332 | if (TREE_STATIC (field)) |
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| 333 | { |
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| 334 | pending_statics = tree_cons (NULL_TREE, field, pending_statics); |
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| 335 | continue; |
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| 336 | } |
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| 337 | /* Enumerators and enum types which are local to this class need not |
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| 338 | be laid out. Likewise for initialized constant fields. */ |
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| 339 | if (TREE_CODE (field) != FIELD_DECL) |
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| 340 | continue; |
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| 341 | |
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| 342 | /* Lay out the field so we know what alignment it needs. |
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| 343 | For a packed field, use the alignment as specified, |
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| 344 | disregarding what the type would want. */ |
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| 345 | if (DECL_PACKED (field)) |
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| 346 | desired_align = DECL_ALIGN (field); |
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| 347 | layout_decl (field, known_align); |
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| 348 | if (! DECL_PACKED (field)) |
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| 349 | desired_align = DECL_ALIGN (field); |
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| 350 | /* Some targets (i.e. VMS) limit struct field alignment |
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| 351 | to a lower boundary than alignment of variables. */ |
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| 352 | #ifdef BIGGEST_FIELD_ALIGNMENT |
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| 353 | desired_align = MIN (desired_align, BIGGEST_FIELD_ALIGNMENT); |
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| 354 | #endif |
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| 355 | |
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| 356 | /* Record must have at least as much alignment as any field. |
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| 357 | Otherwise, the alignment of the field within the record |
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| 358 | is meaningless. */ |
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| 359 | |
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| 360 | #ifndef PCC_BITFIELD_TYPE_MATTERS |
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| 361 | record_align = MAX (record_align, desired_align); |
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| 362 | #else |
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| 363 | if (PCC_BITFIELD_TYPE_MATTERS && TREE_TYPE (field) != error_mark_node |
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| 364 | && DECL_BIT_FIELD_TYPE (field) |
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| 365 | && ! integer_zerop (TYPE_SIZE (TREE_TYPE (field)))) |
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| 366 | { |
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| 367 | /* For these machines, a zero-length field does not |
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| 368 | affect the alignment of the structure as a whole. |
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| 369 | It does, however, affect the alignment of the next field |
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| 370 | within the structure. */ |
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| 371 | if (! integer_zerop (DECL_SIZE (field))) |
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| 372 | record_align = MAX (record_align, desired_align); |
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| 373 | else if (! DECL_PACKED (field)) |
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| 374 | desired_align = TYPE_ALIGN (TREE_TYPE (field)); |
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| 375 | /* A named bit field of declared type `int' |
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| 376 | forces the entire structure to have `int' alignment. */ |
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| 377 | if (DECL_NAME (field) != 0) |
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| 378 | { |
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| 379 | int type_align = TYPE_ALIGN (TREE_TYPE (field)); |
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| 380 | if (maximum_field_alignment != 0) |
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| 381 | type_align = MIN (type_align, maximum_field_alignment); |
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| 382 | else if (flag_pack_struct) |
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| 383 | type_align = MIN (type_align, BITS_PER_UNIT); |
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| 384 | |
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| 385 | record_align = MAX (record_align, type_align); |
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| 386 | } |
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| 387 | } |
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| 388 | else |
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| 389 | record_align = MAX (record_align, desired_align); |
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| 390 | #endif |
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| 391 | |
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| 392 | /* Does this field automatically have alignment it needs |
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| 393 | by virtue of the fields that precede it and the record's |
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| 394 | own alignment? */ |
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| 395 | |
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| 396 | if (const_size % desired_align != 0 |
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| 397 | || (var_align % desired_align != 0 |
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| 398 | && var_size != 0)) |
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| 399 | { |
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| 400 | /* No, we need to skip space before this field. |
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| 401 | Bump the cumulative size to multiple of field alignment. */ |
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| 402 | |
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| 403 | if (var_size == 0 |
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| 404 | || var_align % desired_align == 0) |
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| 405 | const_size |
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| 406 | = CEIL (const_size, desired_align) * desired_align; |
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| 407 | else |
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| 408 | { |
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| 409 | if (const_size > 0) |
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| 410 | var_size = size_binop (PLUS_EXPR, var_size, |
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| 411 | size_int (const_size)); |
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| 412 | const_size = 0; |
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| 413 | var_size = round_up (var_size, desired_align); |
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| 414 | var_align = MIN (var_align, desired_align); |
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| 415 | } |
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| 416 | } |
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| 417 | |
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| 418 | #ifdef PCC_BITFIELD_TYPE_MATTERS |
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| 419 | if (PCC_BITFIELD_TYPE_MATTERS |
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| 420 | && TREE_CODE (field) == FIELD_DECL |
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| 421 | && TREE_TYPE (field) != error_mark_node |
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| 422 | && DECL_BIT_FIELD_TYPE (field) |
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| 423 | && !DECL_PACKED (field) |
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| 424 | /* If #pragma pack is in effect, turn off this feature. */ |
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| 425 | && maximum_field_alignment == 0 |
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| 426 | && !flag_pack_struct |
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| 427 | && !integer_zerop (DECL_SIZE (field))) |
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| 428 | { |
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| 429 | int type_align = TYPE_ALIGN (TREE_TYPE (field)); |
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| 430 | register tree dsize = DECL_SIZE (field); |
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| 431 | int field_size = TREE_INT_CST_LOW (dsize); |
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| 432 | |
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| 433 | /* A bit field may not span the unit of alignment of its type. |
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| 434 | Advance to next boundary if necessary. */ |
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| 435 | /* ??? There is some uncertainty here as to what |
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| 436 | should be done if type_align is less than the width of the type. |
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| 437 | That can happen because the width exceeds BIGGEST_ALIGNMENT |
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| 438 | or because it exceeds maximum_field_alignment. */ |
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| 439 | if (const_size / type_align |
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| 440 | != (const_size + (field_size % type_align) - 1) / type_align) |
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| 441 | const_size = CEIL (const_size, type_align) * type_align; |
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| 442 | } |
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| 443 | #endif |
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| 444 | |
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| 445 | /* No existing machine description uses this parameter. |
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| 446 | So I have made it in this aspect identical to PCC_BITFIELD_TYPE_MATTERS. */ |
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| 447 | #ifdef BITFIELD_NBYTES_LIMITED |
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| 448 | if (BITFIELD_NBYTES_LIMITED |
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| 449 | && TREE_CODE (field) == FIELD_DECL |
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| 450 | && TREE_TYPE (field) != error_mark_node |
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| 451 | && DECL_BIT_FIELD_TYPE (field) |
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| 452 | && !DECL_PACKED (field) |
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| 453 | && !integer_zerop (DECL_SIZE (field))) |
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| 454 | { |
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| 455 | int type_align = TYPE_ALIGN (TREE_TYPE (field)); |
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| 456 | register tree dsize = DECL_SIZE (field); |
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| 457 | int field_size = TREE_INT_CST_LOW (dsize); |
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| 458 | |
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| 459 | if (maximum_field_alignment != 0) |
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| 460 | type_align = MIN (type_align, maximum_field_alignment); |
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| 461 | else if (flag_pack_struct) |
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| 462 | type_align = MIN (type_align, BITS_PER_UNIT); |
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| 463 | |
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| 464 | /* A bit field may not span the unit of alignment of its type. |
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| 465 | Advance to next boundary if necessary. */ |
---|
| 466 | if (const_size / type_align |
---|
| 467 | != (const_size + field_size - 1) / type_align) |
---|
| 468 | const_size = CEIL (const_size, type_align) * type_align; |
---|
| 469 | } |
---|
| 470 | #endif |
---|
| 471 | |
---|
| 472 | /* Size so far becomes the position of this field. */ |
---|
| 473 | |
---|
| 474 | if (var_size && const_size) |
---|
| 475 | DECL_FIELD_BITPOS (field) |
---|
| 476 | = size_binop (PLUS_EXPR, var_size, size_int (const_size)); |
---|
| 477 | else if (var_size) |
---|
| 478 | DECL_FIELD_BITPOS (field) = var_size; |
---|
| 479 | else |
---|
| 480 | { |
---|
| 481 | DECL_FIELD_BITPOS (field) = size_int (const_size); |
---|
| 482 | |
---|
| 483 | /* If this field ended up more aligned than we thought it |
---|
| 484 | would be (we approximate this by seeing if its position |
---|
| 485 | changed), lay out the field again; perhaps we can use an |
---|
| 486 | integral mode for it now. */ |
---|
| 487 | if (known_align != const_size) |
---|
| 488 | layout_decl (field, const_size); |
---|
| 489 | } |
---|
| 490 | |
---|
| 491 | /* Now add size of this field to the size of the record. */ |
---|
| 492 | |
---|
| 493 | { |
---|
| 494 | register tree dsize = DECL_SIZE (field); |
---|
| 495 | |
---|
| 496 | /* This can happen when we have an invalid nested struct definition, |
---|
| 497 | such as struct j { struct j { int i; } }. The error message is |
---|
| 498 | printed in finish_struct. */ |
---|
| 499 | if (dsize == 0) |
---|
| 500 | /* Do nothing. */; |
---|
| 501 | else if (TREE_CODE (dsize) == INTEGER_CST |
---|
| 502 | && TREE_INT_CST_HIGH (dsize) == 0 |
---|
| 503 | && TREE_INT_CST_LOW (dsize) + const_size > const_size) |
---|
| 504 | /* Use const_size if there's no overflow. */ |
---|
| 505 | const_size += TREE_INT_CST_LOW (dsize); |
---|
| 506 | else |
---|
| 507 | { |
---|
| 508 | if (var_size == 0) |
---|
| 509 | var_size = dsize; |
---|
| 510 | else |
---|
| 511 | var_size = size_binop (PLUS_EXPR, var_size, dsize); |
---|
| 512 | } |
---|
| 513 | } |
---|
| 514 | } |
---|
| 515 | |
---|
| 516 | /* Work out the total size and alignment of the record |
---|
| 517 | as one expression and store in the record type. |
---|
| 518 | Round it up to a multiple of the record's alignment. */ |
---|
| 519 | |
---|
| 520 | if (var_size == 0) |
---|
| 521 | { |
---|
| 522 | TYPE_SIZE (rec) = size_int (const_size); |
---|
| 523 | } |
---|
| 524 | else |
---|
| 525 | { |
---|
| 526 | if (const_size) |
---|
| 527 | var_size |
---|
| 528 | = size_binop (PLUS_EXPR, var_size, size_int (const_size)); |
---|
| 529 | TYPE_SIZE (rec) = var_size; |
---|
| 530 | } |
---|
| 531 | |
---|
| 532 | /* Determine the desired alignment. */ |
---|
| 533 | #ifdef ROUND_TYPE_ALIGN |
---|
| 534 | TYPE_ALIGN (rec) = ROUND_TYPE_ALIGN (rec, TYPE_ALIGN (rec), record_align); |
---|
| 535 | #else |
---|
| 536 | TYPE_ALIGN (rec) = MAX (TYPE_ALIGN (rec), record_align); |
---|
| 537 | #endif |
---|
| 538 | |
---|
| 539 | #ifdef ROUND_TYPE_SIZE |
---|
| 540 | TYPE_SIZE (rec) = ROUND_TYPE_SIZE (rec, TYPE_SIZE (rec), TYPE_ALIGN (rec)); |
---|
| 541 | #else |
---|
| 542 | /* Round the size up to be a multiple of the required alignment */ |
---|
| 543 | TYPE_SIZE (rec) = round_up (TYPE_SIZE (rec), TYPE_ALIGN (rec)); |
---|
| 544 | #endif |
---|
| 545 | |
---|
| 546 | return pending_statics; |
---|
| 547 | } |
---|
| 548 | |
---|
| 549 | /* Lay out a UNION_TYPE or QUAL_UNION_TYPE type. |
---|
| 550 | Lay out all the fields, set their positions to zero, |
---|
| 551 | and compute the size and alignment of the union (maximum of any field). |
---|
| 552 | Note that if you set the TYPE_ALIGN before calling this |
---|
| 553 | then the union align is aligned to at least that boundary. */ |
---|
| 554 | |
---|
| 555 | static void |
---|
| 556 | layout_union (rec) |
---|
| 557 | tree rec; |
---|
| 558 | { |
---|
| 559 | register tree field; |
---|
| 560 | #ifdef STRUCTURE_SIZE_BOUNDARY |
---|
| 561 | unsigned union_align = STRUCTURE_SIZE_BOUNDARY; |
---|
| 562 | #else |
---|
| 563 | unsigned union_align = BITS_PER_UNIT; |
---|
| 564 | #endif |
---|
| 565 | |
---|
| 566 | /* The size of the union, based on the fields scanned so far, |
---|
| 567 | is max (CONST_SIZE, VAR_SIZE). |
---|
| 568 | VAR_SIZE may be null; then CONST_SIZE by itself is the size. */ |
---|
| 569 | register int const_size = 0; |
---|
| 570 | register tree var_size = 0; |
---|
| 571 | |
---|
| 572 | /* If this is a QUAL_UNION_TYPE, we want to process the fields in |
---|
| 573 | the reverse order in building the COND_EXPR that denotes its |
---|
| 574 | size. We reverse them again later. */ |
---|
| 575 | if (TREE_CODE (rec) == QUAL_UNION_TYPE) |
---|
| 576 | TYPE_FIELDS (rec) = nreverse (TYPE_FIELDS (rec)); |
---|
| 577 | |
---|
| 578 | for (field = TYPE_FIELDS (rec); field; field = TREE_CHAIN (field)) |
---|
| 579 | { |
---|
| 580 | /* Enums which are local to this class need not be laid out. */ |
---|
| 581 | if (TREE_CODE (field) == CONST_DECL || TREE_CODE (field) == TYPE_DECL) |
---|
| 582 | continue; |
---|
| 583 | |
---|
| 584 | layout_decl (field, 0); |
---|
| 585 | DECL_FIELD_BITPOS (field) = size_int (0); |
---|
| 586 | |
---|
| 587 | /* Union must be at least as aligned as any field requires. */ |
---|
| 588 | |
---|
| 589 | union_align = MAX (union_align, DECL_ALIGN (field)); |
---|
| 590 | |
---|
| 591 | #ifdef PCC_BITFIELD_TYPE_MATTERS |
---|
| 592 | /* On the m88000, a bit field of declare type `int' |
---|
| 593 | forces the entire union to have `int' alignment. */ |
---|
| 594 | if (PCC_BITFIELD_TYPE_MATTERS && DECL_BIT_FIELD_TYPE (field)) |
---|
| 595 | union_align = MAX (union_align, TYPE_ALIGN (TREE_TYPE (field))); |
---|
| 596 | #endif |
---|
| 597 | |
---|
| 598 | if (TREE_CODE (rec) == UNION_TYPE) |
---|
| 599 | { |
---|
| 600 | /* Set union_size to max (decl_size, union_size). |
---|
| 601 | There are more and less general ways to do this. |
---|
| 602 | Use only CONST_SIZE unless forced to use VAR_SIZE. */ |
---|
| 603 | |
---|
| 604 | if (TREE_CODE (DECL_SIZE (field)) == INTEGER_CST) |
---|
| 605 | const_size |
---|
| 606 | = MAX (const_size, TREE_INT_CST_LOW (DECL_SIZE (field))); |
---|
| 607 | else if (var_size == 0) |
---|
| 608 | var_size = DECL_SIZE (field); |
---|
| 609 | else |
---|
| 610 | var_size = size_binop (MAX_EXPR, var_size, DECL_SIZE (field)); |
---|
| 611 | } |
---|
| 612 | else if (TREE_CODE (rec) == QUAL_UNION_TYPE) |
---|
| 613 | var_size = fold (build (COND_EXPR, sizetype, DECL_QUALIFIER (field), |
---|
| 614 | DECL_SIZE (field), |
---|
| 615 | var_size ? var_size : integer_zero_node)); |
---|
| 616 | } |
---|
| 617 | |
---|
| 618 | if (TREE_CODE (rec) == QUAL_UNION_TYPE) |
---|
| 619 | TYPE_FIELDS (rec) = nreverse (TYPE_FIELDS (rec)); |
---|
| 620 | |
---|
| 621 | /* Determine the ultimate size of the union (in bytes). */ |
---|
| 622 | if (NULL == var_size) |
---|
| 623 | TYPE_SIZE (rec) = size_int (CEIL (const_size, BITS_PER_UNIT) |
---|
| 624 | * BITS_PER_UNIT); |
---|
| 625 | else if (const_size == 0) |
---|
| 626 | TYPE_SIZE (rec) = var_size; |
---|
| 627 | else |
---|
| 628 | TYPE_SIZE (rec) = size_binop (MAX_EXPR, var_size, |
---|
| 629 | round_up (size_int (const_size), |
---|
| 630 | BITS_PER_UNIT)); |
---|
| 631 | |
---|
| 632 | /* Determine the desired alignment. */ |
---|
| 633 | #ifdef ROUND_TYPE_ALIGN |
---|
| 634 | TYPE_ALIGN (rec) = ROUND_TYPE_ALIGN (rec, TYPE_ALIGN (rec), union_align); |
---|
| 635 | #else |
---|
| 636 | TYPE_ALIGN (rec) = MAX (TYPE_ALIGN (rec), union_align); |
---|
| 637 | #endif |
---|
| 638 | |
---|
| 639 | #ifdef ROUND_TYPE_SIZE |
---|
| 640 | TYPE_SIZE (rec) = ROUND_TYPE_SIZE (rec, TYPE_SIZE (rec), TYPE_ALIGN (rec)); |
---|
| 641 | #else |
---|
| 642 | /* Round the size up to be a multiple of the required alignment */ |
---|
| 643 | TYPE_SIZE (rec) = round_up (TYPE_SIZE (rec), TYPE_ALIGN (rec)); |
---|
| 644 | #endif |
---|
| 645 | } |
---|
| 646 | |
---|
| 647 | /* Calculate the mode, size, and alignment for TYPE. |
---|
| 648 | For an array type, calculate the element separation as well. |
---|
| 649 | Record TYPE on the chain of permanent or temporary types |
---|
| 650 | so that dbxout will find out about it. |
---|
| 651 | |
---|
| 652 | TYPE_SIZE of a type is nonzero if the type has been laid out already. |
---|
| 653 | layout_type does nothing on such a type. |
---|
| 654 | |
---|
| 655 | If the type is incomplete, its TYPE_SIZE remains zero. */ |
---|
| 656 | |
---|
| 657 | void |
---|
| 658 | layout_type (type) |
---|
| 659 | tree type; |
---|
| 660 | { |
---|
| 661 | int old; |
---|
| 662 | tree pending_statics; |
---|
| 663 | |
---|
| 664 | if (type == 0) |
---|
| 665 | abort (); |
---|
| 666 | |
---|
| 667 | /* Do nothing if type has been laid out before. */ |
---|
| 668 | if (TYPE_SIZE (type)) |
---|
| 669 | return; |
---|
| 670 | |
---|
| 671 | /* Make sure all nodes we allocate are not momentary; |
---|
| 672 | they must last past the current statement. */ |
---|
| 673 | old = suspend_momentary (); |
---|
| 674 | |
---|
| 675 | /* Put all our nodes into the same obstack as the type. Also, |
---|
| 676 | make expressions saveable (this is a no-op for permanent types). */ |
---|
| 677 | |
---|
| 678 | push_obstacks (TYPE_OBSTACK (type), TYPE_OBSTACK (type)); |
---|
| 679 | saveable_allocation (); |
---|
| 680 | |
---|
| 681 | switch (TREE_CODE (type)) |
---|
| 682 | { |
---|
| 683 | case LANG_TYPE: |
---|
| 684 | /* This kind of type is the responsibility |
---|
| 685 | of the language-specific code. */ |
---|
| 686 | abort (); |
---|
| 687 | |
---|
| 688 | case INTEGER_TYPE: |
---|
| 689 | case ENUMERAL_TYPE: |
---|
| 690 | if (TREE_CODE (TYPE_MIN_VALUE (type)) == INTEGER_CST |
---|
| 691 | && tree_int_cst_sgn (TYPE_MIN_VALUE (type)) >= 0) |
---|
| 692 | TREE_UNSIGNED (type) = 1; |
---|
| 693 | |
---|
| 694 | TYPE_MODE (type) = smallest_mode_for_size (TYPE_PRECISION (type), |
---|
| 695 | MODE_INT); |
---|
| 696 | TYPE_SIZE (type) = size_int (GET_MODE_BITSIZE (TYPE_MODE (type))); |
---|
| 697 | break; |
---|
| 698 | |
---|
| 699 | case REAL_TYPE: |
---|
| 700 | TYPE_MODE (type) = mode_for_size (TYPE_PRECISION (type), MODE_FLOAT, 0); |
---|
| 701 | TYPE_SIZE (type) = size_int (GET_MODE_BITSIZE (TYPE_MODE (type))); |
---|
| 702 | break; |
---|
| 703 | |
---|
| 704 | case COMPLEX_TYPE: |
---|
| 705 | TREE_UNSIGNED (type) = TREE_UNSIGNED (TREE_TYPE (type)); |
---|
| 706 | TYPE_MODE (type) |
---|
| 707 | = mode_for_size (2 * TYPE_PRECISION (TREE_TYPE (type)), |
---|
| 708 | (TREE_CODE (TREE_TYPE (type)) == INTEGER_TYPE |
---|
| 709 | ? MODE_COMPLEX_INT : MODE_COMPLEX_FLOAT), |
---|
| 710 | 0); |
---|
| 711 | TYPE_SIZE (type) = size_int (GET_MODE_BITSIZE (TYPE_MODE (type))); |
---|
| 712 | break; |
---|
| 713 | |
---|
| 714 | case VOID_TYPE: |
---|
| 715 | TYPE_SIZE (type) = size_zero_node; |
---|
| 716 | TYPE_ALIGN (type) = 1; |
---|
| 717 | TYPE_MODE (type) = VOIDmode; |
---|
| 718 | break; |
---|
| 719 | |
---|
| 720 | case OFFSET_TYPE: |
---|
| 721 | TYPE_SIZE (type) = size_int (POINTER_SIZE); |
---|
| 722 | TYPE_MODE (type) = ptr_mode; |
---|
| 723 | break; |
---|
| 724 | |
---|
| 725 | case FUNCTION_TYPE: |
---|
| 726 | case METHOD_TYPE: |
---|
| 727 | TYPE_MODE (type) = mode_for_size (2 * POINTER_SIZE, MODE_INT, 0); |
---|
| 728 | TYPE_SIZE (type) = size_int (2 * POINTER_SIZE); |
---|
| 729 | break; |
---|
| 730 | |
---|
| 731 | case POINTER_TYPE: |
---|
| 732 | case REFERENCE_TYPE: |
---|
| 733 | TYPE_MODE (type) = ptr_mode; |
---|
| 734 | TYPE_SIZE (type) = size_int (POINTER_SIZE); |
---|
| 735 | TREE_UNSIGNED (type) = 1; |
---|
| 736 | TYPE_PRECISION (type) = POINTER_SIZE; |
---|
| 737 | break; |
---|
| 738 | |
---|
| 739 | case ARRAY_TYPE: |
---|
| 740 | { |
---|
| 741 | register tree index = TYPE_DOMAIN (type); |
---|
| 742 | register tree element = TREE_TYPE (type); |
---|
| 743 | |
---|
| 744 | build_pointer_type (element); |
---|
| 745 | |
---|
| 746 | /* We need to know both bounds in order to compute the size. */ |
---|
| 747 | if (index && TYPE_MAX_VALUE (index) && TYPE_MIN_VALUE (index) |
---|
| 748 | && TYPE_SIZE (element)) |
---|
| 749 | { |
---|
| 750 | tree ub = TYPE_MAX_VALUE (index); |
---|
| 751 | tree lb = TYPE_MIN_VALUE (index); |
---|
| 752 | tree length; |
---|
| 753 | |
---|
| 754 | /* If UB is max (lb - 1, x), remove the MAX_EXPR since the |
---|
| 755 | test for negative below covers it. */ |
---|
| 756 | if (TREE_CODE (ub) == MAX_EXPR |
---|
| 757 | && TREE_CODE (TREE_OPERAND (ub, 0)) == MINUS_EXPR |
---|
| 758 | && integer_onep (TREE_OPERAND (TREE_OPERAND (ub, 0), 1)) |
---|
| 759 | && operand_equal_p (TREE_OPERAND (TREE_OPERAND (ub, 0), 0), |
---|
| 760 | lb, 0)) |
---|
| 761 | ub = TREE_OPERAND (ub, 1); |
---|
| 762 | else if (TREE_CODE (ub) == MAX_EXPR |
---|
| 763 | && TREE_CODE (TREE_OPERAND (ub, 1)) == MINUS_EXPR |
---|
| 764 | && integer_onep (TREE_OPERAND (TREE_OPERAND (ub, 1), 1)) |
---|
| 765 | && operand_equal_p (TREE_OPERAND (TREE_OPERAND (ub, 1), |
---|
| 766 | 0), |
---|
| 767 | lb, 0)) |
---|
| 768 | ub = TREE_OPERAND (ub, 0); |
---|
| 769 | |
---|
| 770 | length = size_binop (PLUS_EXPR, size_one_node, |
---|
| 771 | size_binop (MINUS_EXPR, ub, lb)); |
---|
| 772 | |
---|
| 773 | /* If neither bound is a constant and sizetype is signed, make |
---|
| 774 | sure the size is never negative. We should really do this |
---|
| 775 | if *either* bound is non-constant, but this is the best |
---|
| 776 | compromise between C and Ada. */ |
---|
| 777 | if (! TREE_UNSIGNED (sizetype) |
---|
| 778 | && TREE_CODE (TYPE_MIN_VALUE (index)) != INTEGER_CST |
---|
| 779 | && TREE_CODE (TYPE_MAX_VALUE (index)) != INTEGER_CST) |
---|
| 780 | length = size_binop (MAX_EXPR, length, size_zero_node); |
---|
| 781 | |
---|
| 782 | TYPE_SIZE (type) = size_binop (MULT_EXPR, length, |
---|
| 783 | TYPE_SIZE (element)); |
---|
| 784 | } |
---|
| 785 | |
---|
| 786 | /* Now round the alignment and size, |
---|
| 787 | using machine-dependent criteria if any. */ |
---|
| 788 | |
---|
| 789 | #ifdef ROUND_TYPE_ALIGN |
---|
| 790 | TYPE_ALIGN (type) |
---|
| 791 | = ROUND_TYPE_ALIGN (type, TYPE_ALIGN (element), BITS_PER_UNIT); |
---|
| 792 | #else |
---|
| 793 | TYPE_ALIGN (type) = MAX (TYPE_ALIGN (element), BITS_PER_UNIT); |
---|
| 794 | #endif |
---|
| 795 | |
---|
| 796 | #ifdef ROUND_TYPE_SIZE |
---|
| 797 | if (TYPE_SIZE (type) != 0) |
---|
| 798 | TYPE_SIZE (type) |
---|
| 799 | = ROUND_TYPE_SIZE (type, TYPE_SIZE (type), TYPE_ALIGN (type)); |
---|
| 800 | #endif |
---|
| 801 | |
---|
| 802 | TYPE_MODE (type) = BLKmode; |
---|
| 803 | if (TYPE_SIZE (type) != 0 |
---|
| 804 | && TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST |
---|
| 805 | /* BLKmode elements force BLKmode aggregate; |
---|
| 806 | else extract/store fields may lose. */ |
---|
| 807 | && (TYPE_MODE (TREE_TYPE (type)) != BLKmode |
---|
| 808 | || TYPE_NO_FORCE_BLK (TREE_TYPE (type)))) |
---|
| 809 | { |
---|
| 810 | TYPE_MODE (type) |
---|
| 811 | = mode_for_size (TREE_INT_CST_LOW (TYPE_SIZE (type)), |
---|
| 812 | MODE_INT, 1); |
---|
| 813 | |
---|
| 814 | if (STRICT_ALIGNMENT && TYPE_ALIGN (type) < BIGGEST_ALIGNMENT |
---|
| 815 | && TYPE_ALIGN (type) < TREE_INT_CST_LOW (TYPE_SIZE (type)) |
---|
| 816 | && TYPE_MODE (type) != BLKmode) |
---|
| 817 | { |
---|
| 818 | TYPE_NO_FORCE_BLK (type) = 1; |
---|
| 819 | TYPE_MODE (type) = BLKmode; |
---|
| 820 | } |
---|
| 821 | } |
---|
| 822 | break; |
---|
| 823 | } |
---|
| 824 | |
---|
| 825 | case RECORD_TYPE: |
---|
| 826 | pending_statics = layout_record (type); |
---|
| 827 | TYPE_MODE (type) = BLKmode; |
---|
| 828 | if (TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST) |
---|
| 829 | { |
---|
| 830 | tree field; |
---|
| 831 | /* A record which has any BLKmode members must itself be BLKmode; |
---|
| 832 | it can't go in a register. |
---|
| 833 | Unless the member is BLKmode only because it isn't aligned. */ |
---|
| 834 | for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field)) |
---|
| 835 | { |
---|
| 836 | int bitpos; |
---|
| 837 | |
---|
| 838 | if (TREE_CODE (field) != FIELD_DECL) |
---|
| 839 | continue; |
---|
| 840 | |
---|
| 841 | if (TYPE_MODE (TREE_TYPE (field)) == BLKmode |
---|
| 842 | && ! TYPE_NO_FORCE_BLK (TREE_TYPE (field))) |
---|
| 843 | goto record_lose; |
---|
| 844 | |
---|
| 845 | if (TREE_CODE (DECL_FIELD_BITPOS (field)) != INTEGER_CST) |
---|
| 846 | goto record_lose; |
---|
| 847 | |
---|
| 848 | bitpos = TREE_INT_CST_LOW (DECL_FIELD_BITPOS (field)); |
---|
| 849 | |
---|
| 850 | /* Must be BLKmode if any field crosses a word boundary, |
---|
| 851 | since extract_bit_field can't handle that in registers. */ |
---|
| 852 | if (bitpos / BITS_PER_WORD |
---|
| 853 | != ((TREE_INT_CST_LOW (DECL_SIZE (field)) + bitpos - 1) |
---|
| 854 | / BITS_PER_WORD) |
---|
| 855 | /* But there is no problem if the field is entire words. */ |
---|
| 856 | && TREE_INT_CST_LOW (DECL_SIZE (field)) % BITS_PER_WORD == 0) |
---|
| 857 | goto record_lose; |
---|
| 858 | } |
---|
| 859 | |
---|
| 860 | TYPE_MODE (type) |
---|
| 861 | = mode_for_size (TREE_INT_CST_LOW (TYPE_SIZE (type)), |
---|
| 862 | MODE_INT, 1); |
---|
| 863 | |
---|
| 864 | /* If structure's known alignment is less than |
---|
| 865 | what the scalar mode would need, and it matters, |
---|
| 866 | then stick with BLKmode. */ |
---|
| 867 | if (STRICT_ALIGNMENT |
---|
| 868 | && ! (TYPE_ALIGN (type) >= BIGGEST_ALIGNMENT |
---|
| 869 | || (TYPE_ALIGN (type) |
---|
| 870 | >= TREE_INT_CST_LOW (TYPE_SIZE (type))))) |
---|
| 871 | { |
---|
| 872 | if (TYPE_MODE (type) != BLKmode) |
---|
| 873 | /* If this is the only reason this type is BLKmode, |
---|
| 874 | then don't force containing types to be BLKmode. */ |
---|
| 875 | TYPE_NO_FORCE_BLK (type) = 1; |
---|
| 876 | TYPE_MODE (type) = BLKmode; |
---|
| 877 | } |
---|
| 878 | |
---|
| 879 | record_lose: ; |
---|
| 880 | } |
---|
| 881 | |
---|
| 882 | /* Lay out any static members. This is done now |
---|
| 883 | because their type may use the record's type. */ |
---|
| 884 | while (pending_statics) |
---|
| 885 | { |
---|
| 886 | layout_decl (TREE_VALUE (pending_statics), 0); |
---|
| 887 | pending_statics = TREE_CHAIN (pending_statics); |
---|
| 888 | } |
---|
| 889 | break; |
---|
| 890 | |
---|
| 891 | case UNION_TYPE: |
---|
| 892 | case QUAL_UNION_TYPE: |
---|
| 893 | layout_union (type); |
---|
| 894 | TYPE_MODE (type) = BLKmode; |
---|
| 895 | if (TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST |
---|
| 896 | /* If structure's known alignment is less than |
---|
| 897 | what the scalar mode would need, and it matters, |
---|
| 898 | then stick with BLKmode. */ |
---|
| 899 | && (! STRICT_ALIGNMENT |
---|
| 900 | || TYPE_ALIGN (type) >= BIGGEST_ALIGNMENT |
---|
| 901 | || TYPE_ALIGN (type) >= TREE_INT_CST_LOW (TYPE_SIZE (type)))) |
---|
| 902 | { |
---|
| 903 | tree field; |
---|
| 904 | /* A union which has any BLKmode members must itself be BLKmode; |
---|
| 905 | it can't go in a register. |
---|
| 906 | Unless the member is BLKmode only because it isn't aligned. */ |
---|
| 907 | for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field)) |
---|
| 908 | { |
---|
| 909 | if (TREE_CODE (field) != FIELD_DECL) |
---|
| 910 | continue; |
---|
| 911 | |
---|
| 912 | if (TYPE_MODE (TREE_TYPE (field)) == BLKmode |
---|
| 913 | && ! TYPE_NO_FORCE_BLK (TREE_TYPE (field))) |
---|
| 914 | goto union_lose; |
---|
| 915 | } |
---|
| 916 | |
---|
| 917 | TYPE_MODE (type) |
---|
| 918 | = mode_for_size (TREE_INT_CST_LOW (TYPE_SIZE (type)), |
---|
| 919 | MODE_INT, 1); |
---|
| 920 | |
---|
| 921 | union_lose: ; |
---|
| 922 | } |
---|
| 923 | break; |
---|
| 924 | |
---|
| 925 | /* Pascal and Chill types */ |
---|
| 926 | case BOOLEAN_TYPE: /* store one byte/boolean for now. */ |
---|
| 927 | TYPE_MODE (type) = QImode; |
---|
| 928 | TYPE_SIZE (type) = size_int (GET_MODE_BITSIZE (TYPE_MODE (type))); |
---|
| 929 | TYPE_PRECISION (type) = 1; |
---|
| 930 | TYPE_ALIGN (type) = GET_MODE_ALIGNMENT (TYPE_MODE (type)); |
---|
| 931 | if (TREE_CODE (TYPE_MIN_VALUE (type)) == INTEGER_CST |
---|
| 932 | && tree_int_cst_sgn (TYPE_MIN_VALUE (type)) >= 0) |
---|
| 933 | TREE_UNSIGNED (type) = 1; |
---|
| 934 | break; |
---|
| 935 | |
---|
| 936 | case CHAR_TYPE: |
---|
| 937 | TYPE_MODE (type) = QImode; |
---|
| 938 | TYPE_SIZE (type) = size_int (GET_MODE_BITSIZE (TYPE_MODE (type))); |
---|
| 939 | TYPE_PRECISION (type) = GET_MODE_BITSIZE (TYPE_MODE (type)); |
---|
| 940 | TYPE_ALIGN (type) = GET_MODE_ALIGNMENT (TYPE_MODE (type)); |
---|
| 941 | break; |
---|
| 942 | |
---|
| 943 | case SET_TYPE: |
---|
| 944 | if (TREE_CODE (TYPE_MAX_VALUE (TYPE_DOMAIN (type))) != INTEGER_CST |
---|
| 945 | || TREE_CODE (TYPE_MIN_VALUE (TYPE_DOMAIN (type))) != INTEGER_CST) |
---|
| 946 | abort(); |
---|
| 947 | else |
---|
| 948 | { |
---|
| 949 | #ifndef SET_WORD_SIZE |
---|
| 950 | #define SET_WORD_SIZE BITS_PER_WORD |
---|
| 951 | #endif |
---|
| 952 | int alignment = set_alignment ? set_alignment : SET_WORD_SIZE; |
---|
| 953 | int size_in_bits = |
---|
| 954 | TREE_INT_CST_LOW (TYPE_MAX_VALUE (TYPE_DOMAIN (type))) |
---|
| 955 | - TREE_INT_CST_LOW (TYPE_MIN_VALUE (TYPE_DOMAIN (type))) + 1; |
---|
| 956 | int rounded_size |
---|
| 957 | = ((size_in_bits + alignment - 1) / alignment) * alignment; |
---|
| 958 | if (rounded_size > alignment) |
---|
| 959 | TYPE_MODE (type) = BLKmode; |
---|
| 960 | else |
---|
| 961 | TYPE_MODE (type) = mode_for_size (alignment, MODE_INT, 1); |
---|
| 962 | TYPE_SIZE (type) = size_int (rounded_size); |
---|
| 963 | TYPE_ALIGN (type) = alignment; |
---|
| 964 | TYPE_PRECISION (type) = size_in_bits; |
---|
| 965 | } |
---|
| 966 | break; |
---|
| 967 | |
---|
| 968 | case FILE_TYPE: |
---|
| 969 | /* The size may vary in different languages, so the language front end |
---|
| 970 | should fill in the size. */ |
---|
| 971 | TYPE_ALIGN (type) = BIGGEST_ALIGNMENT; |
---|
| 972 | TYPE_MODE (type) = BLKmode; |
---|
| 973 | break; |
---|
| 974 | |
---|
| 975 | default: |
---|
| 976 | abort (); |
---|
| 977 | } /* end switch */ |
---|
| 978 | |
---|
| 979 | /* Normally, use the alignment corresponding to the mode chosen. |
---|
| 980 | However, where strict alignment is not required, avoid |
---|
| 981 | over-aligning structures, since most compilers do not do this |
---|
| 982 | alignment. */ |
---|
| 983 | |
---|
| 984 | if (TYPE_MODE (type) != BLKmode && TYPE_MODE (type) != VOIDmode |
---|
| 985 | && (STRICT_ALIGNMENT |
---|
| 986 | || (TREE_CODE (type) != RECORD_TYPE && TREE_CODE (type) != UNION_TYPE |
---|
| 987 | && TREE_CODE (type) != QUAL_UNION_TYPE |
---|
| 988 | && TREE_CODE (type) != ARRAY_TYPE))) |
---|
| 989 | TYPE_ALIGN (type) = GET_MODE_ALIGNMENT (TYPE_MODE (type)); |
---|
| 990 | |
---|
| 991 | /* Evaluate nonconstant size only once, either now or as soon as safe. */ |
---|
| 992 | if (TYPE_SIZE (type) != 0 && TREE_CODE (TYPE_SIZE (type)) != INTEGER_CST) |
---|
| 993 | TYPE_SIZE (type) = variable_size (TYPE_SIZE (type)); |
---|
| 994 | |
---|
| 995 | /* Also layout any other variants of the type. */ |
---|
| 996 | if (TYPE_NEXT_VARIANT (type) |
---|
| 997 | || type != TYPE_MAIN_VARIANT (type)) |
---|
| 998 | { |
---|
| 999 | tree variant; |
---|
| 1000 | /* Record layout info of this variant. */ |
---|
| 1001 | tree size = TYPE_SIZE (type); |
---|
| 1002 | int align = TYPE_ALIGN (type); |
---|
| 1003 | enum machine_mode mode = TYPE_MODE (type); |
---|
| 1004 | |
---|
| 1005 | /* Copy it into all variants. */ |
---|
| 1006 | for (variant = TYPE_MAIN_VARIANT (type); |
---|
| 1007 | variant; |
---|
| 1008 | variant = TYPE_NEXT_VARIANT (variant)) |
---|
| 1009 | { |
---|
| 1010 | TYPE_SIZE (variant) = size; |
---|
| 1011 | TYPE_ALIGN (variant) = align; |
---|
| 1012 | TYPE_MODE (variant) = mode; |
---|
| 1013 | } |
---|
| 1014 | } |
---|
| 1015 | |
---|
| 1016 | pop_obstacks (); |
---|
| 1017 | resume_momentary (old); |
---|
| 1018 | } |
---|
| 1019 | |
---|
| 1020 | /* Create and return a type for signed integers of PRECISION bits. */ |
---|
| 1021 | |
---|
| 1022 | tree |
---|
| 1023 | make_signed_type (precision) |
---|
| 1024 | int precision; |
---|
| 1025 | { |
---|
| 1026 | register tree type = make_node (INTEGER_TYPE); |
---|
| 1027 | |
---|
| 1028 | TYPE_PRECISION (type) = precision; |
---|
| 1029 | |
---|
| 1030 | /* Create the extreme values based on the number of bits. */ |
---|
| 1031 | |
---|
| 1032 | TYPE_MIN_VALUE (type) |
---|
| 1033 | = build_int_2 ((precision - HOST_BITS_PER_WIDE_INT > 0 |
---|
| 1034 | ? 0 : (HOST_WIDE_INT) (-1) << (precision - 1)), |
---|
| 1035 | (((HOST_WIDE_INT) (-1) |
---|
| 1036 | << (precision - HOST_BITS_PER_WIDE_INT - 1 > 0 |
---|
| 1037 | ? precision - HOST_BITS_PER_WIDE_INT - 1 |
---|
| 1038 | : 0)))); |
---|
| 1039 | TYPE_MAX_VALUE (type) |
---|
| 1040 | = build_int_2 ((precision - HOST_BITS_PER_WIDE_INT > 0 |
---|
| 1041 | ? -1 : ((HOST_WIDE_INT) 1 << (precision - 1)) - 1), |
---|
| 1042 | (precision - HOST_BITS_PER_WIDE_INT - 1 > 0 |
---|
| 1043 | ? (((HOST_WIDE_INT) 1 |
---|
| 1044 | << (precision - HOST_BITS_PER_WIDE_INT - 1))) - 1 |
---|
| 1045 | : 0)); |
---|
| 1046 | |
---|
| 1047 | /* Give this type's extreme values this type as their type. */ |
---|
| 1048 | |
---|
| 1049 | TREE_TYPE (TYPE_MIN_VALUE (type)) = type; |
---|
| 1050 | TREE_TYPE (TYPE_MAX_VALUE (type)) = type; |
---|
| 1051 | |
---|
| 1052 | /* The first type made with this or `make_unsigned_type' |
---|
| 1053 | is the type for size values. */ |
---|
| 1054 | |
---|
| 1055 | if (sizetype == 0) |
---|
| 1056 | { |
---|
| 1057 | sizetype = type; |
---|
| 1058 | } |
---|
| 1059 | |
---|
| 1060 | /* Lay out the type: set its alignment, size, etc. */ |
---|
| 1061 | |
---|
| 1062 | layout_type (type); |
---|
| 1063 | |
---|
| 1064 | return type; |
---|
| 1065 | } |
---|
| 1066 | |
---|
| 1067 | /* Create and return a type for unsigned integers of PRECISION bits. */ |
---|
| 1068 | |
---|
| 1069 | tree |
---|
| 1070 | make_unsigned_type (precision) |
---|
| 1071 | int precision; |
---|
| 1072 | { |
---|
| 1073 | register tree type = make_node (INTEGER_TYPE); |
---|
| 1074 | |
---|
| 1075 | TYPE_PRECISION (type) = precision; |
---|
| 1076 | |
---|
| 1077 | /* The first type made with this or `make_signed_type' |
---|
| 1078 | is the type for size values. */ |
---|
| 1079 | |
---|
| 1080 | if (sizetype == 0) |
---|
| 1081 | { |
---|
| 1082 | sizetype = type; |
---|
| 1083 | } |
---|
| 1084 | |
---|
| 1085 | fixup_unsigned_type (type); |
---|
| 1086 | return type; |
---|
| 1087 | } |
---|
| 1088 | |
---|
| 1089 | /* Set the extreme values of TYPE based on its precision in bits, |
---|
| 1090 | then lay it out. Used when make_signed_type won't do |
---|
| 1091 | because the tree code is not INTEGER_TYPE. |
---|
| 1092 | E.g. for Pascal, when the -fsigned-char option is given. */ |
---|
| 1093 | |
---|
| 1094 | void |
---|
| 1095 | fixup_signed_type (type) |
---|
| 1096 | tree type; |
---|
| 1097 | { |
---|
| 1098 | register int precision = TYPE_PRECISION (type); |
---|
| 1099 | |
---|
| 1100 | TYPE_MIN_VALUE (type) |
---|
| 1101 | = build_int_2 ((precision - HOST_BITS_PER_WIDE_INT > 0 |
---|
| 1102 | ? 0 : (HOST_WIDE_INT) (-1) << (precision - 1)), |
---|
| 1103 | (((HOST_WIDE_INT) (-1) |
---|
| 1104 | << (precision - HOST_BITS_PER_WIDE_INT - 1 > 0 |
---|
| 1105 | ? precision - HOST_BITS_PER_WIDE_INT - 1 |
---|
| 1106 | : 0)))); |
---|
| 1107 | TYPE_MAX_VALUE (type) |
---|
| 1108 | = build_int_2 ((precision - HOST_BITS_PER_WIDE_INT > 0 |
---|
| 1109 | ? -1 : ((HOST_WIDE_INT) 1 << (precision - 1)) - 1), |
---|
| 1110 | (precision - HOST_BITS_PER_WIDE_INT - 1 > 0 |
---|
| 1111 | ? (((HOST_WIDE_INT) 1 |
---|
| 1112 | << (precision - HOST_BITS_PER_WIDE_INT - 1))) - 1 |
---|
| 1113 | : 0)); |
---|
| 1114 | |
---|
| 1115 | TREE_TYPE (TYPE_MIN_VALUE (type)) = type; |
---|
| 1116 | TREE_TYPE (TYPE_MAX_VALUE (type)) = type; |
---|
| 1117 | |
---|
| 1118 | /* Lay out the type: set its alignment, size, etc. */ |
---|
| 1119 | |
---|
| 1120 | layout_type (type); |
---|
| 1121 | } |
---|
| 1122 | |
---|
| 1123 | /* Set the extreme values of TYPE based on its precision in bits, |
---|
| 1124 | then lay it out. This is used both in `make_unsigned_type' |
---|
| 1125 | and for enumeral types. */ |
---|
| 1126 | |
---|
| 1127 | void |
---|
| 1128 | fixup_unsigned_type (type) |
---|
| 1129 | tree type; |
---|
| 1130 | { |
---|
| 1131 | register int precision = TYPE_PRECISION (type); |
---|
| 1132 | |
---|
| 1133 | TYPE_MIN_VALUE (type) = build_int_2 (0, 0); |
---|
| 1134 | TYPE_MAX_VALUE (type) |
---|
| 1135 | = build_int_2 (precision - HOST_BITS_PER_WIDE_INT >= 0 |
---|
| 1136 | ? -1 : ((HOST_WIDE_INT) 1 << precision) - 1, |
---|
| 1137 | precision - HOST_BITS_PER_WIDE_INT > 0 |
---|
| 1138 | ? ((unsigned HOST_WIDE_INT) ~0 |
---|
| 1139 | >> (HOST_BITS_PER_WIDE_INT |
---|
| 1140 | - (precision - HOST_BITS_PER_WIDE_INT))) |
---|
| 1141 | : 0); |
---|
| 1142 | TREE_TYPE (TYPE_MIN_VALUE (type)) = type; |
---|
| 1143 | TREE_TYPE (TYPE_MAX_VALUE (type)) = type; |
---|
| 1144 | |
---|
| 1145 | /* Lay out the type: set its alignment, size, etc. */ |
---|
| 1146 | |
---|
| 1147 | layout_type (type); |
---|
| 1148 | } |
---|
| 1149 | |
---|
| 1150 | /* Find the best machine mode to use when referencing a bit field of length |
---|
| 1151 | BITSIZE bits starting at BITPOS. |
---|
| 1152 | |
---|
| 1153 | The underlying object is known to be aligned to a boundary of ALIGN bits. |
---|
| 1154 | If LARGEST_MODE is not VOIDmode, it means that we should not use a mode |
---|
| 1155 | larger than LARGEST_MODE (usually SImode). |
---|
| 1156 | |
---|
| 1157 | If no mode meets all these conditions, we return VOIDmode. Otherwise, if |
---|
| 1158 | VOLATILEP is true or SLOW_BYTE_ACCESS is false, we return the smallest |
---|
| 1159 | mode meeting these conditions. |
---|
| 1160 | |
---|
| 1161 | Otherwise (VOLATILEP is false and SLOW_BYTE_ACCESS is true), we return |
---|
| 1162 | the largest mode (but a mode no wider than UNITS_PER_WORD) that meets |
---|
| 1163 | all the conditions. */ |
---|
| 1164 | |
---|
| 1165 | enum machine_mode |
---|
| 1166 | get_best_mode (bitsize, bitpos, align, largest_mode, volatilep) |
---|
| 1167 | int bitsize, bitpos; |
---|
| 1168 | int align; |
---|
| 1169 | enum machine_mode largest_mode; |
---|
| 1170 | int volatilep; |
---|
| 1171 | { |
---|
| 1172 | enum machine_mode mode; |
---|
| 1173 | int unit; |
---|
| 1174 | |
---|
| 1175 | /* Find the narrowest integer mode that contains the bit field. */ |
---|
| 1176 | for (mode = GET_CLASS_NARROWEST_MODE (MODE_INT); mode != VOIDmode; |
---|
| 1177 | mode = GET_MODE_WIDER_MODE (mode)) |
---|
| 1178 | { |
---|
| 1179 | unit = GET_MODE_BITSIZE (mode); |
---|
| 1180 | if (bitpos / unit == (bitpos + bitsize - 1) / unit) |
---|
| 1181 | break; |
---|
| 1182 | } |
---|
| 1183 | |
---|
| 1184 | if (mode == MAX_MACHINE_MODE |
---|
| 1185 | /* It is tempting to omit the following line |
---|
| 1186 | if STRICT_ALIGNMENT is true. |
---|
| 1187 | But that is incorrect, since if the bitfield uses part of 3 bytes |
---|
| 1188 | and we use a 4-byte mode, we could get a spurious segv |
---|
| 1189 | if the extra 4th byte is past the end of memory. |
---|
| 1190 | (Though at least one Unix compiler ignores this problem: |
---|
| 1191 | that on the Sequent 386 machine. */ |
---|
| 1192 | || MIN (unit, BIGGEST_ALIGNMENT) > align |
---|
| 1193 | || (largest_mode != VOIDmode && unit > GET_MODE_BITSIZE (largest_mode))) |
---|
| 1194 | return VOIDmode; |
---|
| 1195 | |
---|
| 1196 | if (SLOW_BYTE_ACCESS && ! volatilep) |
---|
| 1197 | { |
---|
| 1198 | enum machine_mode wide_mode = VOIDmode, tmode; |
---|
| 1199 | |
---|
| 1200 | for (tmode = GET_CLASS_NARROWEST_MODE (MODE_INT); tmode != VOIDmode; |
---|
| 1201 | tmode = GET_MODE_WIDER_MODE (tmode)) |
---|
| 1202 | { |
---|
| 1203 | unit = GET_MODE_BITSIZE (tmode); |
---|
| 1204 | if (bitpos / unit == (bitpos + bitsize - 1) / unit |
---|
| 1205 | && unit <= BITS_PER_WORD |
---|
| 1206 | && unit <= MIN (align, BIGGEST_ALIGNMENT) |
---|
| 1207 | && (largest_mode == VOIDmode |
---|
| 1208 | || unit <= GET_MODE_BITSIZE (largest_mode))) |
---|
| 1209 | wide_mode = tmode; |
---|
| 1210 | } |
---|
| 1211 | |
---|
| 1212 | if (wide_mode != VOIDmode) |
---|
| 1213 | return wide_mode; |
---|
| 1214 | } |
---|
| 1215 | |
---|
| 1216 | return mode; |
---|
| 1217 | } |
---|
| 1218 | |
---|
| 1219 | /* Save all variables describing the current status into the structure *P. |
---|
| 1220 | This is used before starting a nested function. */ |
---|
| 1221 | |
---|
| 1222 | void |
---|
| 1223 | save_storage_status (p) |
---|
| 1224 | struct function *p; |
---|
| 1225 | { |
---|
| 1226 | #if 0 /* Need not save, since always 0 and non0 (resp.) within a function. */ |
---|
| 1227 | p->pending_sizes = pending_sizes; |
---|
| 1228 | p->immediate_size_expand = immediate_size_expand; |
---|
| 1229 | #endif /* 0 */ |
---|
| 1230 | } |
---|
| 1231 | |
---|
| 1232 | /* Restore all variables describing the current status from the structure *P. |
---|
| 1233 | This is used after a nested function. */ |
---|
| 1234 | |
---|
| 1235 | void |
---|
| 1236 | restore_storage_status (p) |
---|
| 1237 | struct function *p; |
---|
| 1238 | { |
---|
| 1239 | #if 0 |
---|
| 1240 | pending_sizes = p->pending_sizes; |
---|
| 1241 | immediate_size_expand = p->immediate_size_expand; |
---|
| 1242 | #endif /* 0 */ |
---|
| 1243 | } |
---|