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. */ |
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466 | if (const_size / type_align |
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467 | != (const_size + field_size - 1) / type_align) |
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468 | const_size = CEIL (const_size, type_align) * type_align; |
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469 | } |
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470 | #endif |
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471 | |
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472 | /* Size so far becomes the position of this field. */ |
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473 | |
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474 | if (var_size && const_size) |
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475 | DECL_FIELD_BITPOS (field) |
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476 | = size_binop (PLUS_EXPR, var_size, size_int (const_size)); |
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477 | else if (var_size) |
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478 | DECL_FIELD_BITPOS (field) = var_size; |
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479 | else |
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480 | { |
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481 | DECL_FIELD_BITPOS (field) = size_int (const_size); |
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482 | |
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483 | /* If this field ended up more aligned than we thought it |
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484 | would be (we approximate this by seeing if its position |
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485 | changed), lay out the field again; perhaps we can use an |
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486 | integral mode for it now. */ |
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487 | if (known_align != const_size) |
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488 | layout_decl (field, const_size); |
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489 | } |
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490 | |
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491 | /* Now add size of this field to the size of the record. */ |
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492 | |
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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 | } |
---|