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1 ------------------------------------------------------------------------------
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2 -- --
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3 -- GNAT COMPILER COMPONENTS --
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4 -- --
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5 -- S E M _ C A S E --
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6 -- --
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7 -- B o d y --
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8 -- --
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131
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9 -- Copyright (C) 1996-2018, Free Software Foundation, Inc. --
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111
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10 -- --
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11 -- GNAT is free software; you can redistribute it and/or modify it under --
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12 -- terms of the GNU General Public License as published by the Free Soft- --
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13 -- ware Foundation; either version 3, or (at your option) any later ver- --
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14 -- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
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15 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
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16 -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
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17 -- for more details. You should have received a copy of the GNU General --
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18 -- Public License distributed with GNAT; see file COPYING3. If not, go to --
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19 -- http://www.gnu.org/licenses for a complete copy of the license. --
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20 -- --
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21 -- GNAT was originally developed by the GNAT team at New York University. --
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22 -- Extensive contributions were provided by Ada Core Technologies Inc. --
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23 -- --
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24 ------------------------------------------------------------------------------
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25
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26 with Atree; use Atree;
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27 with Einfo; use Einfo;
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28 with Errout; use Errout;
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29 with Namet; use Namet;
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30 with Nlists; use Nlists;
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31 with Nmake; use Nmake;
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32 with Opt; use Opt;
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33 with Sem; use Sem;
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34 with Sem_Aux; use Sem_Aux;
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35 with Sem_Eval; use Sem_Eval;
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36 with Sem_Res; use Sem_Res;
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37 with Sem_Util; use Sem_Util;
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38 with Sem_Type; use Sem_Type;
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39 with Snames; use Snames;
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40 with Stand; use Stand;
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41 with Sinfo; use Sinfo;
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42 with Tbuild; use Tbuild;
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43 with Uintp; use Uintp;
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44
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45 with Ada.Unchecked_Deallocation;
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46
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47 with GNAT.Heap_Sort_G;
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48
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49 package body Sem_Case is
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50
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51 type Choice_Bounds is record
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52 Lo : Node_Id;
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53 Hi : Node_Id;
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54 Node : Node_Id;
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55 end record;
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56 -- Represent one choice bounds entry with Lo and Hi values, Node points
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57 -- to the choice node itself.
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58
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59 type Choice_Table_Type is array (Nat range <>) of Choice_Bounds;
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60 -- Table type used to sort the choices present in a case statement or
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61 -- record variant. The actual entries are stored in 1 .. Last, but we
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62 -- have a 0 entry for use in sorting.
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63
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64 -----------------------
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65 -- Local Subprograms --
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66 -----------------------
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67
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68 procedure Check_Choice_Set
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69 (Choice_Table : in out Choice_Table_Type;
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70 Bounds_Type : Entity_Id;
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71 Subtyp : Entity_Id;
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72 Others_Present : Boolean;
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73 Case_Node : Node_Id);
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74 -- This is the procedure which verifies that a set of case alternatives
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75 -- or record variant choices has no duplicates, and covers the range
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76 -- specified by Bounds_Type. Choice_Table contains the discrete choices
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77 -- to check. These must start at position 1.
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78 --
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79 -- Furthermore Choice_Table (0) must exist. This element is used by
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80 -- the sorting algorithm as a temporary. Others_Present is a flag
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81 -- indicating whether or not an Others choice is present. Finally
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82 -- Msg_Sloc gives the source location of the construct containing the
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83 -- choices in the Choice_Table.
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84 --
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85 -- Bounds_Type is the type whose range must be covered by the alternatives
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86 --
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87 -- Subtyp is the subtype of the expression. If its bounds are non-static
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88 -- the alternatives must cover its base type.
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89
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90 function Choice_Image (Value : Uint; Ctype : Entity_Id) return Name_Id;
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91 -- Given a Pos value of enumeration type Ctype, returns the name
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92 -- ID of an appropriate string to be used in error message output.
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93
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94 procedure Expand_Others_Choice
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95 (Case_Table : Choice_Table_Type;
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96 Others_Choice : Node_Id;
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97 Choice_Type : Entity_Id);
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98 -- The case table is the table generated by a call to Check_Choices
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99 -- (with just 1 .. Last_Choice entries present). Others_Choice is a
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100 -- pointer to the N_Others_Choice node (this routine is only called if
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101 -- an others choice is present), and Choice_Type is the discrete type
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102 -- of the bounds. The effect of this call is to analyze the cases and
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103 -- determine the set of values covered by others. This choice list is
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104 -- set in the Others_Discrete_Choices field of the N_Others_Choice node.
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105
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106 ----------------------
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107 -- Check_Choice_Set --
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108 ----------------------
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109
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110 procedure Check_Choice_Set
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111 (Choice_Table : in out Choice_Table_Type;
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112 Bounds_Type : Entity_Id;
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113 Subtyp : Entity_Id;
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114 Others_Present : Boolean;
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115 Case_Node : Node_Id)
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116 is
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117 Predicate_Error : Boolean := False;
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118 -- Flag to prevent cascaded errors when a static predicate is known to
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119 -- be violated by one choice.
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120
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121 Num_Choices : constant Nat := Choice_Table'Last;
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122
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123 procedure Check_Against_Predicate
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124 (Pred : in out Node_Id;
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125 Choice : Choice_Bounds;
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126 Prev_Lo : in out Uint;
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127 Prev_Hi : in out Uint;
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128 Error : in out Boolean);
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129 -- Determine whether a choice covers legal values as defined by a static
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130 -- predicate set. Pred is a static predicate range. Choice is the choice
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131 -- to be examined. Prev_Lo and Prev_Hi are the bounds of the previous
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132 -- choice that covered a predicate set. Error denotes whether the check
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133 -- found an illegal intersection.
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134
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135 procedure Check_Duplicates;
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136 -- Check for duplicate choices, and call Dup_Choice if there are any
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137 -- such errors. Note that predicates are irrelevant here.
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138
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139 procedure Dup_Choice (Lo, Hi : Uint; C : Node_Id);
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140 -- Post message "duplication of choice value(s) bla bla at xx". Message
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141 -- is posted at location C. Caller sets Error_Msg_Sloc for xx.
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142
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143 procedure Explain_Non_Static_Bound;
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144 -- Called when we find a non-static bound, requiring the base type to
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145 -- be covered. Provides where possible a helpful explanation of why the
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146 -- bounds are non-static, since this is not always obvious.
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147
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148 function Lt_Choice (C1, C2 : Natural) return Boolean;
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149 -- Comparison routine for comparing Choice_Table entries. Use the lower
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150 -- bound of each Choice as the key.
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151
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152 procedure Missing_Choice (Value1 : Node_Id; Value2 : Node_Id);
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153 procedure Missing_Choice (Value1 : Node_Id; Value2 : Uint);
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154 procedure Missing_Choice (Value1 : Uint; Value2 : Node_Id);
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155 procedure Missing_Choice (Value1 : Uint; Value2 : Uint);
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156 -- Issue an error message indicating that there are missing choices,
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157 -- followed by the image of the missing choices themselves which lie
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158 -- between Value1 and Value2 inclusive.
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159
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160 procedure Missing_Choices (Pred : Node_Id; Prev_Hi : Uint);
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161 -- Emit an error message for each non-covered static predicate set.
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162 -- Prev_Hi denotes the upper bound of the last choice covering a set.
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163
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164 procedure Move_Choice (From : Natural; To : Natural);
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165 -- Move routine for sorting the Choice_Table
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166
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167 package Sorting is new GNAT.Heap_Sort_G (Move_Choice, Lt_Choice);
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168
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169 -----------------------------
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170 -- Check_Against_Predicate --
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171 -----------------------------
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172
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173 procedure Check_Against_Predicate
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174 (Pred : in out Node_Id;
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175 Choice : Choice_Bounds;
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176 Prev_Lo : in out Uint;
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177 Prev_Hi : in out Uint;
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178 Error : in out Boolean)
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179 is
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180 procedure Illegal_Range
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181 (Loc : Source_Ptr;
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182 Lo : Uint;
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183 Hi : Uint);
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184 -- Emit an error message regarding a choice that clashes with the
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185 -- legal static predicate sets. Loc is the location of the choice
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186 -- that introduced the illegal range. Lo .. Hi is the range.
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187
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188 function Inside_Range
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189 (Lo : Uint;
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190 Hi : Uint;
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191 Val : Uint) return Boolean;
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192 -- Determine whether position Val within a discrete type is within
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193 -- the range Lo .. Hi inclusive.
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194
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195 -------------------
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196 -- Illegal_Range --
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197 -------------------
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198
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199 procedure Illegal_Range
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200 (Loc : Source_Ptr;
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201 Lo : Uint;
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202 Hi : Uint)
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203 is
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204 begin
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205 Error_Msg_Name_1 := Chars (Bounds_Type);
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206
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207 -- Single value
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208
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209 if Lo = Hi then
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210 if Is_Integer_Type (Bounds_Type) then
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211 Error_Msg_Uint_1 := Lo;
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212 Error_Msg ("static predicate on % excludes value ^!", Loc);
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213 else
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214 Error_Msg_Name_2 := Choice_Image (Lo, Bounds_Type);
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215 Error_Msg ("static predicate on % excludes value %!", Loc);
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216 end if;
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217
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218 -- Range
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219
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220 else
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221 if Is_Integer_Type (Bounds_Type) then
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222 Error_Msg_Uint_1 := Lo;
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223 Error_Msg_Uint_2 := Hi;
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224 Error_Msg
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225 ("static predicate on % excludes range ^ .. ^!", Loc);
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226 else
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227 Error_Msg_Name_2 := Choice_Image (Lo, Bounds_Type);
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228 Error_Msg_Name_3 := Choice_Image (Hi, Bounds_Type);
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229 Error_Msg
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230 ("static predicate on % excludes range % .. %!", Loc);
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231 end if;
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232 end if;
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233 end Illegal_Range;
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234
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235 ------------------
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236 -- Inside_Range --
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237 ------------------
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238
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239 function Inside_Range
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240 (Lo : Uint;
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241 Hi : Uint;
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242 Val : Uint) return Boolean
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243 is
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244 begin
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245 return Lo <= Val and then Val <= Hi;
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246 end Inside_Range;
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247
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248 -- Local variables
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249
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250 Choice_Hi : constant Uint := Expr_Value (Choice.Hi);
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251 Choice_Lo : constant Uint := Expr_Value (Choice.Lo);
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252 Loc : Source_Ptr;
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253 LocN : Node_Id;
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254 Next_Hi : Uint;
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255 Next_Lo : Uint;
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256 Pred_Hi : Uint;
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257 Pred_Lo : Uint;
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258
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259 -- Start of processing for Check_Against_Predicate
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260
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261 begin
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262 -- Find the proper error message location
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263
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264 if Present (Choice.Node) then
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265 LocN := Choice.Node;
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266 else
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267 LocN := Case_Node;
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268 end if;
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269
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270 Loc := Sloc (LocN);
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271
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272 if Present (Pred) then
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273 Pred_Lo := Expr_Value (Low_Bound (Pred));
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274 Pred_Hi := Expr_Value (High_Bound (Pred));
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275
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276 -- Previous choices managed to satisfy all static predicate sets
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277
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278 else
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279 Illegal_Range (Loc, Choice_Lo, Choice_Hi);
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280 Error := True;
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281 return;
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282 end if;
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283
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284 -- Step 1: Ignore duplicate choices, other than to set the flag,
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285 -- because these were already detected by Check_Duplicates.
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286
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287 if Inside_Range (Choice_Lo, Choice_Hi, Prev_Lo)
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288 or else Inside_Range (Choice_Lo, Choice_Hi, Prev_Hi)
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289 then
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290 Error := True;
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291
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292 -- Step 2: Detect full coverage
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293
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294 -- Choice_Lo Choice_Hi
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295 -- +============+
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296 -- Pred_Lo Pred_Hi
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297
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298 elsif Choice_Lo = Pred_Lo and then Choice_Hi = Pred_Hi then
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299 Prev_Lo := Choice_Lo;
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300 Prev_Hi := Choice_Hi;
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301 Next (Pred);
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302
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303 -- Step 3: Detect all cases where a choice mentions values that are
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304 -- not part of the static predicate sets.
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305
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306 -- Choice_Lo Choice_Hi Pred_Lo Pred_Hi
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307 -- +-----------+ . . . . . +=========+
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308 -- ^ illegal ^
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309
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310 elsif Choice_Lo < Pred_Lo and then Choice_Hi < Pred_Lo then
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311 Illegal_Range (Loc, Choice_Lo, Choice_Hi);
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312 Error := True;
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313
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314 -- Choice_Lo Pred_Lo Choice_Hi Pred_Hi
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315 -- +-----------+=========+===========+
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316 -- ^ illegal ^
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317
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318 elsif Choice_Lo < Pred_Lo
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319 and then Inside_Range (Pred_Lo, Pred_Hi, Choice_Hi)
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320 then
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321 Illegal_Range (Loc, Choice_Lo, Pred_Lo - 1);
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322 Error := True;
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323
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324 -- Pred_Lo Pred_Hi Choice_Lo Choice_Hi
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325 -- +=========+ . . . . +-----------+
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326 -- ^ illegal ^
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327
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328 elsif Pred_Lo < Choice_Lo and then Pred_Hi < Choice_Lo then
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329 if Others_Present then
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330
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331 -- Current predicate set is covered by others clause.
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332
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333 null;
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334
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335 else
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336 Missing_Choice (Pred_Lo, Pred_Hi);
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337 Error := True;
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338 end if;
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339
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340 -- There may be several static predicate sets between the current
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341 -- one and the choice. Inspect the next static predicate set.
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342
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343 Next (Pred);
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344 Check_Against_Predicate
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345 (Pred => Pred,
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346 Choice => Choice,
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347 Prev_Lo => Prev_Lo,
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348 Prev_Hi => Prev_Hi,
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349 Error => Error);
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350
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351 -- Pred_Lo Choice_Lo Pred_Hi Choice_Hi
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352 -- +=========+===========+-----------+
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353 -- ^ illegal ^
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354
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355 elsif Pred_Hi < Choice_Hi
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356 and then Inside_Range (Pred_Lo, Pred_Hi, Choice_Lo)
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357 then
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358 Next (Pred);
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359
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360 -- The choice may fall in a static predicate set. If this is the
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361 -- case, avoid mentioning legal values in the error message.
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362
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363 if Present (Pred) then
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364 Next_Lo := Expr_Value (Low_Bound (Pred));
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365 Next_Hi := Expr_Value (High_Bound (Pred));
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366
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367 -- The next static predicate set is to the right of the choice
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368
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369 if Choice_Hi < Next_Lo and then Choice_Hi < Next_Hi then
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370 Illegal_Range (Loc, Pred_Hi + 1, Choice_Hi);
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371 else
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372 Illegal_Range (Loc, Pred_Hi + 1, Next_Lo - 1);
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373 end if;
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374 else
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375 Illegal_Range (Loc, Pred_Hi + 1, Choice_Hi);
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376 end if;
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377
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378 Error := True;
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379
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380 -- Choice_Lo Pred_Lo Pred_Hi Choice_Hi
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381 -- +-----------+=========+-----------+
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382 -- ^ illegal ^ ^ illegal ^
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383
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384 -- Emit an error on the low gap, disregard the upper gap
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385
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386 elsif Choice_Lo < Pred_Lo and then Pred_Hi < Choice_Hi then
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387 Illegal_Range (Loc, Choice_Lo, Pred_Lo - 1);
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388 Error := True;
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389
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390 -- Step 4: Detect all cases of partial or missing coverage
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391
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392 -- Pred_Lo Choice_Lo Choice_Hi Pred_Hi
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393 -- +=========+==========+===========+
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394 -- ^ gap ^ ^ gap ^
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395
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396 else
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397 -- An "others" choice covers all gaps
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398
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399 if Others_Present then
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400 Prev_Lo := Choice_Lo;
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401 Prev_Hi := Choice_Hi;
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402
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403 -- Check whether predicate set is fully covered by choice
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404
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405 if Pred_Hi = Choice_Hi then
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406 Next (Pred);
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407 end if;
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408
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409 -- Choice_Lo Choice_Hi Pred_Hi
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410 -- +===========+===========+
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411 -- Pred_Lo ^ gap ^
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412
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413 -- The upper gap may be covered by a subsequent choice
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414
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415 elsif Pred_Lo = Choice_Lo then
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416 Prev_Lo := Choice_Lo;
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417 Prev_Hi := Choice_Hi;
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418
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419 -- Pred_Lo Prev_Hi Choice_Lo Choice_Hi Pred_Hi
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420 -- +===========+=========+===========+===========+
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421 -- ^ covered ^ ^ gap ^
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422
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423 else pragma Assert (Pred_Lo < Choice_Lo);
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424
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425 -- A previous choice covered the gap up to the current choice
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426
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427 if Prev_Hi = Choice_Lo - 1 then
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428 Prev_Lo := Choice_Lo;
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429 Prev_Hi := Choice_Hi;
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430
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431 if Choice_Hi = Pred_Hi then
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432 Next (Pred);
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433 end if;
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434
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435 -- The previous choice did not intersect with the current
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436 -- static predicate set.
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437
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438 elsif Prev_Hi < Pred_Lo then
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439 Missing_Choice (Pred_Lo, Choice_Lo - 1);
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440 Error := True;
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441
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442 -- The previous choice covered part of the static predicate set
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443 -- but there is a gap after Prev_Hi.
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444
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445 else
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446 Missing_Choice (Prev_Hi + 1, Choice_Lo - 1);
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447 Error := True;
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448 end if;
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449 end if;
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450 end if;
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451 end Check_Against_Predicate;
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452
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453 ----------------------
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454 -- Check_Duplicates --
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455 ----------------------
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456
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457 procedure Check_Duplicates is
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458 Choice : Node_Id;
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459 Choice_Hi : Uint;
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460 Choice_Lo : Uint;
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461 Prev_Choice : Node_Id;
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462 pragma Warnings (Off, Prev_Choice);
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463 Prev_Hi : Uint;
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464
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465 begin
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466 Prev_Hi := Expr_Value (Choice_Table (1).Hi);
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467
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468 for Outer_Index in 2 .. Num_Choices loop
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469 Choice_Lo := Expr_Value (Choice_Table (Outer_Index).Lo);
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470 Choice_Hi := Expr_Value (Choice_Table (Outer_Index).Hi);
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471
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472 -- Choices overlap; this is an error
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473
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474 if Choice_Lo <= Prev_Hi then
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475 Choice := Choice_Table (Outer_Index).Node;
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476
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477 -- Find first previous choice that overlaps
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478
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479 for Inner_Index in 1 .. Outer_Index - 1 loop
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480 if Choice_Lo <=
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481 Expr_Value (Choice_Table (Inner_Index).Hi)
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482 then
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483 Prev_Choice := Choice_Table (Inner_Index).Node;
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484 exit;
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485 end if;
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486 end loop;
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487
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488 if Sloc (Prev_Choice) <= Sloc (Choice) then
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489 Error_Msg_Sloc := Sloc (Prev_Choice);
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490 Dup_Choice (Choice_Lo, UI_Min (Choice_Hi, Prev_Hi), Choice);
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491 else
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492 Error_Msg_Sloc := Sloc (Choice);
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493 Dup_Choice
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494 (Choice_Lo, UI_Min (Choice_Hi, Prev_Hi), Prev_Choice);
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495 end if;
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496 end if;
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497
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498 if Choice_Hi > Prev_Hi then
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499 Prev_Hi := Choice_Hi;
|
|
500 end if;
|
|
501 end loop;
|
|
502 end Check_Duplicates;
|
|
503
|
|
504 ----------------
|
|
505 -- Dup_Choice --
|
|
506 ----------------
|
|
507
|
|
508 procedure Dup_Choice (Lo, Hi : Uint; C : Node_Id) is
|
|
509 begin
|
|
510 -- In some situations, we call this with a null range, and obviously
|
|
511 -- we don't want to complain in this case.
|
|
512
|
|
513 if Lo > Hi then
|
|
514 return;
|
|
515 end if;
|
|
516
|
|
517 -- Case of only one value that is duplicated
|
|
518
|
|
519 if Lo = Hi then
|
|
520
|
|
521 -- Integer type
|
|
522
|
|
523 if Is_Integer_Type (Bounds_Type) then
|
|
524
|
|
525 -- We have an integer value, Lo, but if the given choice
|
|
526 -- placement is a constant with that value, then use the
|
|
527 -- name of that constant instead in the message:
|
|
528
|
|
529 if Nkind (C) = N_Identifier
|
|
530 and then Compile_Time_Known_Value (C)
|
|
531 and then Expr_Value (C) = Lo
|
|
532 then
|
|
533 Error_Msg_N ("duplication of choice value: &#!", C);
|
|
534
|
|
535 -- Not that special case, so just output the integer value
|
|
536
|
|
537 else
|
|
538 Error_Msg_Uint_1 := Lo;
|
|
539 Error_Msg_N ("duplication of choice value: ^#!", C);
|
|
540 end if;
|
|
541
|
|
542 -- Enumeration type
|
|
543
|
|
544 else
|
|
545 Error_Msg_Name_1 := Choice_Image (Lo, Bounds_Type);
|
|
546 Error_Msg_N ("duplication of choice value: %#!", C);
|
|
547 end if;
|
|
548
|
|
549 -- More than one choice value, so print range of values
|
|
550
|
|
551 else
|
|
552 -- Integer type
|
|
553
|
|
554 if Is_Integer_Type (Bounds_Type) then
|
|
555
|
|
556 -- Similar to the above, if C is a range of known values which
|
|
557 -- match Lo and Hi, then use the names. We have to go to the
|
|
558 -- original nodes, since the values will have been rewritten
|
|
559 -- to their integer values.
|
|
560
|
|
561 if Nkind (C) = N_Range
|
|
562 and then Nkind (Original_Node (Low_Bound (C))) = N_Identifier
|
|
563 and then Nkind (Original_Node (High_Bound (C))) = N_Identifier
|
|
564 and then Compile_Time_Known_Value (Low_Bound (C))
|
|
565 and then Compile_Time_Known_Value (High_Bound (C))
|
|
566 and then Expr_Value (Low_Bound (C)) = Lo
|
|
567 and then Expr_Value (High_Bound (C)) = Hi
|
|
568 then
|
|
569 Error_Msg_Node_2 := Original_Node (High_Bound (C));
|
|
570 Error_Msg_N
|
|
571 ("duplication of choice values: & .. &#!",
|
|
572 Original_Node (Low_Bound (C)));
|
|
573
|
|
574 -- Not that special case, output integer values
|
|
575
|
|
576 else
|
|
577 Error_Msg_Uint_1 := Lo;
|
|
578 Error_Msg_Uint_2 := Hi;
|
|
579 Error_Msg_N ("duplication of choice values: ^ .. ^#!", C);
|
|
580 end if;
|
|
581
|
|
582 -- Enumeration type
|
|
583
|
|
584 else
|
|
585 Error_Msg_Name_1 := Choice_Image (Lo, Bounds_Type);
|
|
586 Error_Msg_Name_2 := Choice_Image (Hi, Bounds_Type);
|
|
587 Error_Msg_N ("duplication of choice values: % .. %#!", C);
|
|
588 end if;
|
|
589 end if;
|
|
590 end Dup_Choice;
|
|
591
|
|
592 ------------------------------
|
|
593 -- Explain_Non_Static_Bound --
|
|
594 ------------------------------
|
|
595
|
|
596 procedure Explain_Non_Static_Bound is
|
|
597 Expr : Node_Id;
|
|
598
|
|
599 begin
|
|
600 if Nkind (Case_Node) = N_Variant_Part then
|
|
601 Expr := Name (Case_Node);
|
|
602 else
|
|
603 Expr := Expression (Case_Node);
|
|
604 end if;
|
|
605
|
|
606 if Bounds_Type /= Subtyp then
|
|
607
|
|
608 -- If the case is a variant part, the expression is given by the
|
|
609 -- discriminant itself, and the bounds are the culprits.
|
|
610
|
|
611 if Nkind (Case_Node) = N_Variant_Part then
|
|
612 Error_Msg_NE
|
|
613 ("bounds of & are not static, "
|
|
614 & "alternatives must cover base type!", Expr, Expr);
|
|
615
|
|
616 -- If this is a case statement, the expression may be non-static
|
|
617 -- or else the subtype may be at fault.
|
|
618
|
|
619 elsif Is_Entity_Name (Expr) then
|
|
620 Error_Msg_NE
|
|
621 ("bounds of & are not static, "
|
|
622 & "alternatives must cover base type!", Expr, Expr);
|
|
623
|
|
624 else
|
|
625 Error_Msg_N
|
|
626 ("subtype of expression is not static, "
|
|
627 & "alternatives must cover base type!", Expr);
|
|
628 end if;
|
|
629
|
|
630 -- Otherwise the expression is not static, even if the bounds of the
|
|
631 -- type are, or else there are missing alternatives. If both, the
|
|
632 -- additional information may be redundant but harmless. Examine
|
|
633 -- whether original node is an entity, because it may have been
|
|
634 -- constant-folded to a literal if value is known.
|
|
635
|
|
636 elsif not Is_Entity_Name (Original_Node (Expr)) then
|
|
637 Error_Msg_N
|
|
638 ("subtype of expression is not static, "
|
|
639 & "alternatives must cover base type!", Expr);
|
|
640 end if;
|
|
641 end Explain_Non_Static_Bound;
|
|
642
|
|
643 ---------------
|
|
644 -- Lt_Choice --
|
|
645 ---------------
|
|
646
|
|
647 function Lt_Choice (C1, C2 : Natural) return Boolean is
|
|
648 begin
|
|
649 return
|
|
650 Expr_Value (Choice_Table (Nat (C1)).Lo)
|
|
651 <
|
|
652 Expr_Value (Choice_Table (Nat (C2)).Lo);
|
|
653 end Lt_Choice;
|
|
654
|
|
655 --------------------
|
|
656 -- Missing_Choice --
|
|
657 --------------------
|
|
658
|
|
659 procedure Missing_Choice (Value1 : Node_Id; Value2 : Node_Id) is
|
|
660 begin
|
|
661 Missing_Choice (Expr_Value (Value1), Expr_Value (Value2));
|
|
662 end Missing_Choice;
|
|
663
|
|
664 procedure Missing_Choice (Value1 : Node_Id; Value2 : Uint) is
|
|
665 begin
|
|
666 Missing_Choice (Expr_Value (Value1), Value2);
|
|
667 end Missing_Choice;
|
|
668
|
|
669 procedure Missing_Choice (Value1 : Uint; Value2 : Node_Id) is
|
|
670 begin
|
|
671 Missing_Choice (Value1, Expr_Value (Value2));
|
|
672 end Missing_Choice;
|
|
673
|
|
674 --------------------
|
|
675 -- Missing_Choice --
|
|
676 --------------------
|
|
677
|
|
678 procedure Missing_Choice (Value1 : Uint; Value2 : Uint) is
|
|
679 Msg_Sloc : constant Source_Ptr := Sloc (Case_Node);
|
|
680
|
|
681 begin
|
|
682 -- AI05-0188 : within an instance the non-others choices do not have
|
|
683 -- to belong to the actual subtype.
|
|
684
|
|
685 if Ada_Version >= Ada_2012 and then In_Instance then
|
|
686 return;
|
|
687
|
|
688 -- In some situations, we call this with a null range, and obviously
|
|
689 -- we don't want to complain in this case.
|
|
690
|
|
691 elsif Value1 > Value2 then
|
|
692 return;
|
|
693
|
|
694 -- If predicate is already known to be violated, do no check for
|
|
695 -- coverage error, to prevent cascaded messages.
|
|
696
|
|
697 elsif Predicate_Error then
|
|
698 return;
|
|
699 end if;
|
|
700
|
|
701 -- Case of only one value that is missing
|
|
702
|
|
703 if Value1 = Value2 then
|
|
704 if Is_Integer_Type (Bounds_Type) then
|
|
705 Error_Msg_Uint_1 := Value1;
|
|
706 Error_Msg ("missing case value: ^!", Msg_Sloc);
|
|
707 else
|
|
708 Error_Msg_Name_1 := Choice_Image (Value1, Bounds_Type);
|
|
709 Error_Msg ("missing case value: %!", Msg_Sloc);
|
|
710 end if;
|
|
711
|
|
712 -- More than one choice value, so print range of values
|
|
713
|
|
714 else
|
|
715 if Is_Integer_Type (Bounds_Type) then
|
|
716 Error_Msg_Uint_1 := Value1;
|
|
717 Error_Msg_Uint_2 := Value2;
|
|
718 Error_Msg ("missing case values: ^ .. ^!", Msg_Sloc);
|
|
719 else
|
|
720 Error_Msg_Name_1 := Choice_Image (Value1, Bounds_Type);
|
|
721 Error_Msg_Name_2 := Choice_Image (Value2, Bounds_Type);
|
|
722 Error_Msg ("missing case values: % .. %!", Msg_Sloc);
|
|
723 end if;
|
|
724 end if;
|
|
725 end Missing_Choice;
|
|
726
|
|
727 ---------------------
|
|
728 -- Missing_Choices --
|
|
729 ---------------------
|
|
730
|
|
731 procedure Missing_Choices (Pred : Node_Id; Prev_Hi : Uint) is
|
|
732 Hi : Uint;
|
|
733 Lo : Uint;
|
|
734 Set : Node_Id;
|
|
735
|
|
736 begin
|
|
737 Set := Pred;
|
|
738 while Present (Set) loop
|
|
739 Lo := Expr_Value (Low_Bound (Set));
|
|
740 Hi := Expr_Value (High_Bound (Set));
|
|
741
|
|
742 -- A choice covered part of a static predicate set
|
|
743
|
|
744 if Lo <= Prev_Hi and then Prev_Hi < Hi then
|
|
745 Missing_Choice (Prev_Hi + 1, Hi);
|
|
746
|
|
747 else
|
|
748 Missing_Choice (Lo, Hi);
|
|
749 end if;
|
|
750
|
|
751 Next (Set);
|
|
752 end loop;
|
|
753 end Missing_Choices;
|
|
754
|
|
755 -----------------
|
|
756 -- Move_Choice --
|
|
757 -----------------
|
|
758
|
|
759 procedure Move_Choice (From : Natural; To : Natural) is
|
|
760 begin
|
|
761 Choice_Table (Nat (To)) := Choice_Table (Nat (From));
|
|
762 end Move_Choice;
|
|
763
|
|
764 -- Local variables
|
|
765
|
|
766 Bounds_Hi : constant Node_Id := Type_High_Bound (Bounds_Type);
|
|
767 Bounds_Lo : constant Node_Id := Type_Low_Bound (Bounds_Type);
|
|
768 Has_Predicate : constant Boolean :=
|
|
769 Is_OK_Static_Subtype (Bounds_Type)
|
|
770 and then Has_Static_Predicate (Bounds_Type);
|
|
771
|
|
772 Choice_Hi : Uint;
|
|
773 Choice_Lo : Uint;
|
|
774 Pred : Node_Id;
|
|
775 Prev_Lo : Uint;
|
|
776 Prev_Hi : Uint;
|
|
777
|
|
778 -- Start of processing for Check_Choice_Set
|
|
779
|
|
780 begin
|
|
781 -- If the case is part of a predicate aspect specification, do not
|
|
782 -- recheck it against itself.
|
|
783
|
|
784 if Present (Parent (Case_Node))
|
|
785 and then Nkind (Parent (Case_Node)) = N_Aspect_Specification
|
|
786 then
|
|
787 return;
|
|
788 end if;
|
|
789
|
|
790 -- Choice_Table must start at 0 which is an unused location used by the
|
|
791 -- sorting algorithm. However the first valid position for a discrete
|
|
792 -- choice is 1.
|
|
793
|
|
794 pragma Assert (Choice_Table'First = 0);
|
|
795
|
|
796 -- The choices do not cover the base range. Emit an error if "others" is
|
|
797 -- not available and return as there is no need for further processing.
|
|
798
|
|
799 if Num_Choices = 0 then
|
|
800 if not Others_Present then
|
|
801 Missing_Choice (Bounds_Lo, Bounds_Hi);
|
|
802 end if;
|
|
803
|
|
804 return;
|
|
805 end if;
|
|
806
|
|
807 Sorting.Sort (Positive (Choice_Table'Last));
|
|
808
|
|
809 -- First check for duplicates. This involved the choices; predicates, if
|
|
810 -- any, are irrelevant.
|
|
811
|
|
812 Check_Duplicates;
|
|
813
|
|
814 -- Then check for overlaps
|
|
815
|
|
816 -- If the subtype has a static predicate, the predicate defines subsets
|
|
817 -- of legal values and requires finer-grained analysis.
|
|
818
|
|
819 -- Note that in GNAT the predicate is considered static if the predicate
|
|
820 -- expression is static, independently of whether the aspect mentions
|
|
821 -- Static explicitly.
|
|
822
|
|
823 if Has_Predicate then
|
|
824 Pred := First (Static_Discrete_Predicate (Bounds_Type));
|
|
825
|
|
826 -- Make initial value smaller than 'First of type, so that first
|
|
827 -- range comparison succeeds. This applies both to integer types
|
|
828 -- and to enumeration types.
|
|
829
|
|
830 Prev_Lo := Expr_Value (Type_Low_Bound (Bounds_Type)) - 1;
|
|
831 Prev_Hi := Prev_Lo;
|
|
832
|
|
833 declare
|
|
834 Error : Boolean := False;
|
|
835 begin
|
|
836 for Index in 1 .. Num_Choices loop
|
|
837 Check_Against_Predicate
|
|
838 (Pred => Pred,
|
|
839 Choice => Choice_Table (Index),
|
|
840 Prev_Lo => Prev_Lo,
|
|
841 Prev_Hi => Prev_Hi,
|
|
842 Error => Error);
|
|
843
|
|
844 -- The analysis detected an illegal intersection between a
|
|
845 -- choice and a static predicate set. Do not examine other
|
|
846 -- choices unless all errors are requested.
|
|
847
|
|
848 if Error then
|
|
849 Predicate_Error := True;
|
|
850
|
|
851 if not All_Errors_Mode then
|
|
852 return;
|
|
853 end if;
|
|
854 end if;
|
|
855 end loop;
|
|
856 end;
|
|
857
|
|
858 if Predicate_Error then
|
|
859 return;
|
|
860 end if;
|
|
861
|
|
862 -- The choices may legally cover some of the static predicate sets,
|
|
863 -- but not all. Emit an error for each non-covered set.
|
|
864
|
|
865 if not Others_Present then
|
|
866 Missing_Choices (Pred, Prev_Hi);
|
|
867 end if;
|
|
868
|
|
869 -- Default analysis
|
|
870
|
|
871 else
|
|
872 Choice_Lo := Expr_Value (Choice_Table (1).Lo);
|
|
873 Choice_Hi := Expr_Value (Choice_Table (1).Hi);
|
|
874 Prev_Hi := Choice_Hi;
|
|
875
|
|
876 if not Others_Present and then Expr_Value (Bounds_Lo) < Choice_Lo then
|
|
877 Missing_Choice (Bounds_Lo, Choice_Lo - 1);
|
|
878
|
|
879 -- If values are missing outside of the subtype, add explanation.
|
|
880 -- No additional message if only one value is missing.
|
|
881
|
|
882 if Expr_Value (Bounds_Lo) < Choice_Lo - 1 then
|
|
883 Explain_Non_Static_Bound;
|
|
884 end if;
|
|
885 end if;
|
|
886
|
|
887 for Index in 2 .. Num_Choices loop
|
|
888 Choice_Lo := Expr_Value (Choice_Table (Index).Lo);
|
|
889 Choice_Hi := Expr_Value (Choice_Table (Index).Hi);
|
|
890
|
|
891 if Choice_Lo > Prev_Hi + 1 and then not Others_Present then
|
|
892 Missing_Choice (Prev_Hi + 1, Choice_Lo - 1);
|
|
893 end if;
|
|
894
|
|
895 if Choice_Hi > Prev_Hi then
|
|
896 Prev_Hi := Choice_Hi;
|
|
897 end if;
|
|
898 end loop;
|
|
899
|
|
900 if not Others_Present and then Expr_Value (Bounds_Hi) > Prev_Hi then
|
|
901 Missing_Choice (Prev_Hi + 1, Bounds_Hi);
|
|
902
|
|
903 if Expr_Value (Bounds_Hi) > Prev_Hi + 1 then
|
|
904 Explain_Non_Static_Bound;
|
|
905 end if;
|
|
906 end if;
|
|
907 end if;
|
|
908 end Check_Choice_Set;
|
|
909
|
|
910 ------------------
|
|
911 -- Choice_Image --
|
|
912 ------------------
|
|
913
|
|
914 function Choice_Image (Value : Uint; Ctype : Entity_Id) return Name_Id is
|
|
915 Rtp : constant Entity_Id := Root_Type (Ctype);
|
|
916 Lit : Entity_Id;
|
|
917 C : Int;
|
|
918
|
|
919 begin
|
|
920 -- For character, or wide [wide] character. If 7-bit ASCII graphic
|
|
921 -- range, then build and return appropriate character literal name
|
|
922
|
|
923 if Is_Standard_Character_Type (Ctype) then
|
|
924 C := UI_To_Int (Value);
|
|
925
|
|
926 if C in 16#20# .. 16#7E# then
|
|
927 Set_Character_Literal_Name (Char_Code (UI_To_Int (Value)));
|
|
928 return Name_Find;
|
|
929 end if;
|
|
930
|
|
931 -- For user defined enumeration type, find enum/char literal
|
|
932
|
|
933 else
|
|
934 Lit := First_Literal (Rtp);
|
|
935
|
|
936 for J in 1 .. UI_To_Int (Value) loop
|
|
937 Next_Literal (Lit);
|
|
938 end loop;
|
|
939
|
|
940 -- If enumeration literal, just return its value
|
|
941
|
|
942 if Nkind (Lit) = N_Defining_Identifier then
|
|
943 return Chars (Lit);
|
|
944
|
|
945 -- For character literal, get the name and use it if it is
|
|
946 -- for a 7-bit ASCII graphic character in 16#20#..16#7E#.
|
|
947
|
|
948 else
|
|
949 Get_Decoded_Name_String (Chars (Lit));
|
|
950
|
|
951 if Name_Len = 3
|
|
952 and then Name_Buffer (2) in
|
|
953 Character'Val (16#20#) .. Character'Val (16#7E#)
|
|
954 then
|
|
955 return Chars (Lit);
|
|
956 end if;
|
|
957 end if;
|
|
958 end if;
|
|
959
|
|
960 -- If we fall through, we have a character literal which is not in
|
|
961 -- the 7-bit ASCII graphic set. For such cases, we construct the
|
|
962 -- name "type'val(nnn)" where type is the choice type, and nnn is
|
|
963 -- the pos value passed as an argument to Choice_Image.
|
|
964
|
|
965 Get_Name_String (Chars (First_Subtype (Ctype)));
|
|
966
|
|
967 Add_Str_To_Name_Buffer ("'val(");
|
|
968 UI_Image (Value);
|
|
969 Add_Str_To_Name_Buffer (UI_Image_Buffer (1 .. UI_Image_Length));
|
|
970 Add_Char_To_Name_Buffer (')');
|
|
971 return Name_Find;
|
|
972 end Choice_Image;
|
|
973
|
|
974 --------------------------
|
|
975 -- Expand_Others_Choice --
|
|
976 --------------------------
|
|
977
|
|
978 procedure Expand_Others_Choice
|
|
979 (Case_Table : Choice_Table_Type;
|
|
980 Others_Choice : Node_Id;
|
|
981 Choice_Type : Entity_Id)
|
|
982 is
|
|
983 Loc : constant Source_Ptr := Sloc (Others_Choice);
|
|
984 Choice_List : constant List_Id := New_List;
|
|
985 Choice : Node_Id;
|
|
986 Exp_Lo : Node_Id;
|
|
987 Exp_Hi : Node_Id;
|
|
988 Hi : Uint;
|
|
989 Lo : Uint;
|
|
990 Previous_Hi : Uint;
|
|
991
|
|
992 function Build_Choice (Value1, Value2 : Uint) return Node_Id;
|
|
993 -- Builds a node representing the missing choices given by Value1 and
|
|
994 -- Value2. A N_Range node is built if there is more than one literal
|
|
995 -- value missing. Otherwise a single N_Integer_Literal, N_Identifier
|
|
996 -- or N_Character_Literal is built depending on what Choice_Type is.
|
|
997
|
|
998 function Lit_Of (Value : Uint) return Node_Id;
|
|
999 -- Returns the Node_Id for the enumeration literal corresponding to the
|
|
1000 -- position given by Value within the enumeration type Choice_Type.
|
|
1001
|
|
1002 ------------------
|
|
1003 -- Build_Choice --
|
|
1004 ------------------
|
|
1005
|
|
1006 function Build_Choice (Value1, Value2 : Uint) return Node_Id is
|
|
1007 Lit_Node : Node_Id;
|
|
1008 Lo, Hi : Node_Id;
|
|
1009
|
|
1010 begin
|
|
1011 -- If there is only one choice value missing between Value1 and
|
|
1012 -- Value2, build an integer or enumeration literal to represent it.
|
|
1013
|
|
1014 if (Value2 - Value1) = 0 then
|
|
1015 if Is_Integer_Type (Choice_Type) then
|
|
1016 Lit_Node := Make_Integer_Literal (Loc, Value1);
|
|
1017 Set_Etype (Lit_Node, Choice_Type);
|
|
1018 else
|
|
1019 Lit_Node := Lit_Of (Value1);
|
|
1020 end if;
|
|
1021
|
|
1022 -- Otherwise is more that one choice value that is missing between
|
|
1023 -- Value1 and Value2, therefore build a N_Range node of either
|
|
1024 -- integer or enumeration literals.
|
|
1025
|
|
1026 else
|
|
1027 if Is_Integer_Type (Choice_Type) then
|
|
1028 Lo := Make_Integer_Literal (Loc, Value1);
|
|
1029 Set_Etype (Lo, Choice_Type);
|
|
1030 Hi := Make_Integer_Literal (Loc, Value2);
|
|
1031 Set_Etype (Hi, Choice_Type);
|
|
1032 Lit_Node :=
|
|
1033 Make_Range (Loc,
|
|
1034 Low_Bound => Lo,
|
|
1035 High_Bound => Hi);
|
|
1036
|
|
1037 else
|
|
1038 Lit_Node :=
|
|
1039 Make_Range (Loc,
|
|
1040 Low_Bound => Lit_Of (Value1),
|
|
1041 High_Bound => Lit_Of (Value2));
|
|
1042 end if;
|
|
1043 end if;
|
|
1044
|
|
1045 return Lit_Node;
|
|
1046 end Build_Choice;
|
|
1047
|
|
1048 ------------
|
|
1049 -- Lit_Of --
|
|
1050 ------------
|
|
1051
|
|
1052 function Lit_Of (Value : Uint) return Node_Id is
|
|
1053 Lit : Entity_Id;
|
|
1054
|
|
1055 begin
|
|
1056 -- In the case where the literal is of type Character, there needs
|
|
1057 -- to be some special handling since there is no explicit chain
|
|
1058 -- of literals to search. Instead, a N_Character_Literal node
|
|
1059 -- is created with the appropriate Char_Code and Chars fields.
|
|
1060
|
|
1061 if Is_Standard_Character_Type (Choice_Type) then
|
|
1062 Set_Character_Literal_Name (Char_Code (UI_To_Int (Value)));
|
|
1063 Lit := New_Node (N_Character_Literal, Loc);
|
|
1064 Set_Chars (Lit, Name_Find);
|
|
1065 Set_Char_Literal_Value (Lit, Value);
|
|
1066 Set_Etype (Lit, Choice_Type);
|
|
1067 Set_Is_Static_Expression (Lit, True);
|
|
1068 return Lit;
|
|
1069
|
|
1070 -- Otherwise, iterate through the literals list of Choice_Type
|
|
1071 -- "Value" number of times until the desired literal is reached
|
|
1072 -- and then return an occurrence of it.
|
|
1073
|
|
1074 else
|
|
1075 Lit := First_Literal (Choice_Type);
|
|
1076 for J in 1 .. UI_To_Int (Value) loop
|
|
1077 Next_Literal (Lit);
|
|
1078 end loop;
|
|
1079
|
|
1080 return New_Occurrence_Of (Lit, Loc);
|
|
1081 end if;
|
|
1082 end Lit_Of;
|
|
1083
|
|
1084 -- Start of processing for Expand_Others_Choice
|
|
1085
|
|
1086 begin
|
|
1087 if Case_Table'Last = 0 then
|
|
1088
|
|
1089 -- Special case: only an others case is present. The others case
|
|
1090 -- covers the full range of the type.
|
|
1091
|
|
1092 if Is_OK_Static_Subtype (Choice_Type) then
|
|
1093 Choice := New_Occurrence_Of (Choice_Type, Loc);
|
|
1094 else
|
|
1095 Choice := New_Occurrence_Of (Base_Type (Choice_Type), Loc);
|
|
1096 end if;
|
|
1097
|
|
1098 Set_Others_Discrete_Choices (Others_Choice, New_List (Choice));
|
|
1099 return;
|
|
1100 end if;
|
|
1101
|
|
1102 -- Establish the bound values for the choice depending upon whether the
|
|
1103 -- type of the case statement is static or not.
|
|
1104
|
|
1105 if Is_OK_Static_Subtype (Choice_Type) then
|
|
1106 Exp_Lo := Type_Low_Bound (Choice_Type);
|
|
1107 Exp_Hi := Type_High_Bound (Choice_Type);
|
|
1108 else
|
|
1109 Exp_Lo := Type_Low_Bound (Base_Type (Choice_Type));
|
|
1110 Exp_Hi := Type_High_Bound (Base_Type (Choice_Type));
|
|
1111 end if;
|
|
1112
|
|
1113 Lo := Expr_Value (Case_Table (1).Lo);
|
|
1114 Hi := Expr_Value (Case_Table (1).Hi);
|
|
1115 Previous_Hi := Expr_Value (Case_Table (1).Hi);
|
|
1116
|
|
1117 -- Build the node for any missing choices that are smaller than any
|
|
1118 -- explicit choices given in the case.
|
|
1119
|
|
1120 if Expr_Value (Exp_Lo) < Lo then
|
|
1121 Append (Build_Choice (Expr_Value (Exp_Lo), Lo - 1), Choice_List);
|
|
1122 end if;
|
|
1123
|
|
1124 -- Build the nodes representing any missing choices that lie between
|
|
1125 -- the explicit ones given in the case.
|
|
1126
|
|
1127 for J in 2 .. Case_Table'Last loop
|
|
1128 Lo := Expr_Value (Case_Table (J).Lo);
|
|
1129 Hi := Expr_Value (Case_Table (J).Hi);
|
|
1130
|
|
1131 if Lo /= (Previous_Hi + 1) then
|
|
1132 Append_To (Choice_List, Build_Choice (Previous_Hi + 1, Lo - 1));
|
|
1133 end if;
|
|
1134
|
|
1135 Previous_Hi := Hi;
|
|
1136 end loop;
|
|
1137
|
|
1138 -- Build the node for any missing choices that are greater than any
|
|
1139 -- explicit choices given in the case.
|
|
1140
|
|
1141 if Expr_Value (Exp_Hi) > Hi then
|
|
1142 Append (Build_Choice (Hi + 1, Expr_Value (Exp_Hi)), Choice_List);
|
|
1143 end if;
|
|
1144
|
|
1145 Set_Others_Discrete_Choices (Others_Choice, Choice_List);
|
|
1146
|
|
1147 -- Warn on null others list if warning option set
|
|
1148
|
|
1149 if Warn_On_Redundant_Constructs
|
|
1150 and then Comes_From_Source (Others_Choice)
|
|
1151 and then Is_Empty_List (Choice_List)
|
|
1152 then
|
|
1153 Error_Msg_N ("?r?OTHERS choice is redundant", Others_Choice);
|
|
1154 Error_Msg_N ("\?r?previous choices cover all values", Others_Choice);
|
|
1155 end if;
|
|
1156 end Expand_Others_Choice;
|
|
1157
|
|
1158 -----------
|
|
1159 -- No_OP --
|
|
1160 -----------
|
|
1161
|
|
1162 procedure No_OP (C : Node_Id) is
|
|
1163 begin
|
|
1164 if Nkind (C) = N_Range and then Warn_On_Redundant_Constructs then
|
|
1165 Error_Msg_N ("choice is an empty range?r?", C);
|
|
1166 end if;
|
|
1167 end No_OP;
|
|
1168
|
|
1169 -----------------------------
|
|
1170 -- Generic_Analyze_Choices --
|
|
1171 -----------------------------
|
|
1172
|
|
1173 package body Generic_Analyze_Choices is
|
|
1174
|
|
1175 -- The following type is used to gather the entries for the choice
|
|
1176 -- table, so that we can then allocate the right length.
|
|
1177
|
|
1178 type Link;
|
|
1179 type Link_Ptr is access all Link;
|
|
1180
|
|
1181 type Link is record
|
|
1182 Val : Choice_Bounds;
|
|
1183 Nxt : Link_Ptr;
|
|
1184 end record;
|
|
1185
|
|
1186 ---------------------
|
|
1187 -- Analyze_Choices --
|
|
1188 ---------------------
|
|
1189
|
|
1190 procedure Analyze_Choices
|
|
1191 (Alternatives : List_Id;
|
|
1192 Subtyp : Entity_Id)
|
|
1193 is
|
|
1194 Choice_Type : constant Entity_Id := Base_Type (Subtyp);
|
|
1195 -- The actual type against which the discrete choices are resolved.
|
|
1196 -- Note that this type is always the base type not the subtype of the
|
|
1197 -- ruling expression, index or discriminant.
|
|
1198
|
|
1199 Expected_Type : Entity_Id;
|
|
1200 -- The expected type of each choice. Equal to Choice_Type, except if
|
|
1201 -- the expression is universal, in which case the choices can be of
|
|
1202 -- any integer type.
|
|
1203
|
|
1204 Alt : Node_Id;
|
|
1205 -- A case statement alternative or a variant in a record type
|
|
1206 -- declaration.
|
|
1207
|
|
1208 Choice : Node_Id;
|
|
1209 Kind : Node_Kind;
|
|
1210 -- The node kind of the current Choice
|
|
1211
|
|
1212 begin
|
|
1213 -- Set Expected type (= choice type except for universal integer,
|
|
1214 -- where we accept any integer type as a choice).
|
|
1215
|
|
1216 if Choice_Type = Universal_Integer then
|
|
1217 Expected_Type := Any_Integer;
|
|
1218 else
|
|
1219 Expected_Type := Choice_Type;
|
|
1220 end if;
|
|
1221
|
|
1222 -- Now loop through the case alternatives or record variants
|
|
1223
|
|
1224 Alt := First (Alternatives);
|
|
1225 while Present (Alt) loop
|
|
1226
|
|
1227 -- If pragma, just analyze it
|
|
1228
|
|
1229 if Nkind (Alt) = N_Pragma then
|
|
1230 Analyze (Alt);
|
|
1231
|
|
1232 -- Otherwise we have an alternative. In most cases the semantic
|
|
1233 -- processing leaves the list of choices unchanged
|
|
1234
|
|
1235 -- Check each choice against its base type
|
|
1236
|
|
1237 else
|
|
1238 Choice := First (Discrete_Choices (Alt));
|
|
1239 while Present (Choice) loop
|
|
1240 Analyze (Choice);
|
|
1241 Kind := Nkind (Choice);
|
|
1242
|
|
1243 -- Choice is a Range
|
|
1244
|
|
1245 if Kind = N_Range
|
|
1246 or else (Kind = N_Attribute_Reference
|
|
1247 and then Attribute_Name (Choice) = Name_Range)
|
|
1248 then
|
|
1249 Resolve (Choice, Expected_Type);
|
|
1250
|
|
1251 -- Choice is a subtype name, nothing further to do now
|
|
1252
|
|
1253 elsif Is_Entity_Name (Choice)
|
|
1254 and then Is_Type (Entity (Choice))
|
|
1255 then
|
|
1256 null;
|
|
1257
|
|
1258 -- Choice is a subtype indication
|
|
1259
|
|
1260 elsif Kind = N_Subtype_Indication then
|
|
1261 Resolve_Discrete_Subtype_Indication
|
|
1262 (Choice, Expected_Type);
|
|
1263
|
|
1264 -- Others choice, no analysis needed
|
|
1265
|
|
1266 elsif Kind = N_Others_Choice then
|
|
1267 null;
|
|
1268
|
|
1269 -- Only other possibility is an expression
|
|
1270
|
|
1271 else
|
|
1272 Resolve (Choice, Expected_Type);
|
|
1273 end if;
|
|
1274
|
|
1275 -- Move to next choice
|
|
1276
|
|
1277 Next (Choice);
|
|
1278 end loop;
|
|
1279
|
|
1280 Process_Associated_Node (Alt);
|
|
1281 end if;
|
|
1282
|
|
1283 Next (Alt);
|
|
1284 end loop;
|
|
1285 end Analyze_Choices;
|
|
1286
|
|
1287 end Generic_Analyze_Choices;
|
|
1288
|
|
1289 ---------------------------
|
|
1290 -- Generic_Check_Choices --
|
|
1291 ---------------------------
|
|
1292
|
|
1293 package body Generic_Check_Choices is
|
|
1294
|
|
1295 -- The following type is used to gather the entries for the choice
|
|
1296 -- table, so that we can then allocate the right length.
|
|
1297
|
|
1298 type Link;
|
|
1299 type Link_Ptr is access all Link;
|
|
1300
|
|
1301 type Link is record
|
|
1302 Val : Choice_Bounds;
|
|
1303 Nxt : Link_Ptr;
|
|
1304 end record;
|
|
1305
|
|
1306 procedure Free is new Ada.Unchecked_Deallocation (Link, Link_Ptr);
|
|
1307
|
|
1308 -------------------
|
|
1309 -- Check_Choices --
|
|
1310 -------------------
|
|
1311
|
|
1312 procedure Check_Choices
|
|
1313 (N : Node_Id;
|
|
1314 Alternatives : List_Id;
|
|
1315 Subtyp : Entity_Id;
|
|
1316 Others_Present : out Boolean)
|
|
1317 is
|
|
1318 E : Entity_Id;
|
|
1319
|
|
1320 Raises_CE : Boolean;
|
|
1321 -- Set True if one of the bounds of a choice raises CE
|
|
1322
|
|
1323 Enode : Node_Id;
|
|
1324 -- This is where we post error messages for bounds out of range
|
|
1325
|
|
1326 Choice_List : Link_Ptr := null;
|
|
1327 -- Gather list of choices
|
|
1328
|
|
1329 Num_Choices : Nat := 0;
|
|
1330 -- Number of entries in Choice_List
|
|
1331
|
|
1332 Choice_Type : constant Entity_Id := Base_Type (Subtyp);
|
|
1333 -- The actual type against which the discrete choices are resolved.
|
|
1334 -- Note that this type is always the base type not the subtype of the
|
|
1335 -- ruling expression, index or discriminant.
|
|
1336
|
|
1337 Bounds_Type : Entity_Id;
|
|
1338 -- The type from which are derived the bounds of the values covered
|
|
1339 -- by the discrete choices (see 3.8.1 (4)). If a discrete choice
|
|
1340 -- specifies a value outside of these bounds we have an error.
|
|
1341
|
|
1342 Bounds_Lo : Uint;
|
|
1343 Bounds_Hi : Uint;
|
|
1344 -- The actual bounds of the above type
|
|
1345
|
|
1346 Expected_Type : Entity_Id;
|
|
1347 -- The expected type of each choice. Equal to Choice_Type, except if
|
|
1348 -- the expression is universal, in which case the choices can be of
|
|
1349 -- any integer type.
|
|
1350
|
|
1351 Alt : Node_Id;
|
|
1352 -- A case statement alternative or a variant in a record type
|
|
1353 -- declaration.
|
|
1354
|
|
1355 Choice : Node_Id;
|
|
1356 Kind : Node_Kind;
|
|
1357 -- The node kind of the current Choice
|
|
1358
|
|
1359 Others_Choice : Node_Id := Empty;
|
|
1360 -- Remember others choice if it is present (empty otherwise)
|
|
1361
|
|
1362 procedure Check (Choice : Node_Id; Lo, Hi : Node_Id);
|
|
1363 -- Checks the validity of the bounds of a choice. When the bounds
|
|
1364 -- are static and no error occurred the bounds are collected for
|
|
1365 -- later entry into the choices table so that they can be sorted
|
|
1366 -- later on.
|
|
1367
|
|
1368 procedure Handle_Static_Predicate
|
|
1369 (Typ : Entity_Id;
|
|
1370 Lo : Node_Id;
|
|
1371 Hi : Node_Id);
|
|
1372 -- If the type of the alternative has predicates, we must examine
|
|
1373 -- each subset of the predicate rather than the bounds of the type
|
|
1374 -- itself. This is relevant when the choice is a subtype mark or a
|
|
1375 -- subtype indication.
|
|
1376
|
|
1377 -----------
|
|
1378 -- Check --
|
|
1379 -----------
|
|
1380
|
|
1381 procedure Check (Choice : Node_Id; Lo, Hi : Node_Id) is
|
|
1382 Lo_Val : Uint;
|
|
1383 Hi_Val : Uint;
|
|
1384
|
|
1385 begin
|
|
1386 -- First check if an error was already detected on either bounds
|
|
1387
|
|
1388 if Etype (Lo) = Any_Type or else Etype (Hi) = Any_Type then
|
|
1389 return;
|
|
1390
|
|
1391 -- Do not insert non static choices in the table to be sorted
|
|
1392
|
|
1393 elsif not Is_OK_Static_Expression (Lo)
|
|
1394 or else
|
|
1395 not Is_OK_Static_Expression (Hi)
|
|
1396 then
|
|
1397 Process_Non_Static_Choice (Choice);
|
|
1398 return;
|
|
1399
|
|
1400 -- Ignore range which raise constraint error
|
|
1401
|
|
1402 elsif Raises_Constraint_Error (Lo)
|
|
1403 or else Raises_Constraint_Error (Hi)
|
|
1404 then
|
|
1405 Raises_CE := True;
|
|
1406 return;
|
|
1407
|
|
1408 -- AI05-0188 : Within an instance the non-others choices do not
|
|
1409 -- have to belong to the actual subtype.
|
|
1410
|
|
1411 elsif Ada_Version >= Ada_2012 and then In_Instance then
|
|
1412 return;
|
|
1413
|
|
1414 -- Otherwise we have an OK static choice
|
|
1415
|
|
1416 else
|
|
1417 Lo_Val := Expr_Value (Lo);
|
|
1418 Hi_Val := Expr_Value (Hi);
|
|
1419
|
|
1420 -- Do not insert null ranges in the choices table
|
|
1421
|
|
1422 if Lo_Val > Hi_Val then
|
|
1423 Process_Empty_Choice (Choice);
|
|
1424 return;
|
|
1425 end if;
|
|
1426 end if;
|
|
1427
|
|
1428 -- Check for low bound out of range
|
|
1429
|
|
1430 if Lo_Val < Bounds_Lo then
|
|
1431
|
|
1432 -- If the choice is an entity name, then it is a type, and we
|
|
1433 -- want to post the message on the reference to this entity.
|
|
1434 -- Otherwise post it on the lower bound of the range.
|
|
1435
|
|
1436 if Is_Entity_Name (Choice) then
|
|
1437 Enode := Choice;
|
|
1438 else
|
|
1439 Enode := Lo;
|
|
1440 end if;
|
|
1441
|
|
1442 -- Specialize message for integer/enum type
|
|
1443
|
|
1444 if Is_Integer_Type (Bounds_Type) then
|
|
1445 Error_Msg_Uint_1 := Bounds_Lo;
|
|
1446 Error_Msg_N ("minimum allowed choice value is^", Enode);
|
|
1447 else
|
|
1448 Error_Msg_Name_1 := Choice_Image (Bounds_Lo, Bounds_Type);
|
|
1449 Error_Msg_N ("minimum allowed choice value is%", Enode);
|
|
1450 end if;
|
|
1451 end if;
|
|
1452
|
|
1453 -- Check for high bound out of range
|
|
1454
|
|
1455 if Hi_Val > Bounds_Hi then
|
|
1456
|
|
1457 -- If the choice is an entity name, then it is a type, and we
|
|
1458 -- want to post the message on the reference to this entity.
|
|
1459 -- Otherwise post it on the upper bound of the range.
|
|
1460
|
|
1461 if Is_Entity_Name (Choice) then
|
|
1462 Enode := Choice;
|
|
1463 else
|
|
1464 Enode := Hi;
|
|
1465 end if;
|
|
1466
|
|
1467 -- Specialize message for integer/enum type
|
|
1468
|
|
1469 if Is_Integer_Type (Bounds_Type) then
|
|
1470 Error_Msg_Uint_1 := Bounds_Hi;
|
|
1471 Error_Msg_N ("maximum allowed choice value is^", Enode);
|
|
1472 else
|
|
1473 Error_Msg_Name_1 := Choice_Image (Bounds_Hi, Bounds_Type);
|
|
1474 Error_Msg_N ("maximum allowed choice value is%", Enode);
|
|
1475 end if;
|
|
1476 end if;
|
|
1477
|
|
1478 -- Collect bounds in the list
|
|
1479
|
|
1480 -- Note: we still store the bounds, even if they are out of range,
|
|
1481 -- since this may prevent unnecessary cascaded errors for values
|
|
1482 -- that are covered by such an excessive range.
|
|
1483
|
|
1484 Choice_List :=
|
|
1485 new Link'(Val => (Lo, Hi, Choice), Nxt => Choice_List);
|
|
1486 Num_Choices := Num_Choices + 1;
|
|
1487 end Check;
|
|
1488
|
|
1489 -----------------------------
|
|
1490 -- Handle_Static_Predicate --
|
|
1491 -----------------------------
|
|
1492
|
|
1493 procedure Handle_Static_Predicate
|
|
1494 (Typ : Entity_Id;
|
|
1495 Lo : Node_Id;
|
|
1496 Hi : Node_Id)
|
|
1497 is
|
|
1498 P : Node_Id;
|
|
1499 C : Node_Id;
|
|
1500
|
|
1501 begin
|
|
1502 -- Loop through entries in predicate list, checking each entry.
|
|
1503 -- Note that if the list is empty, corresponding to a False
|
|
1504 -- predicate, then no choices are checked. If the choice comes
|
|
1505 -- from a subtype indication, the given range may have bounds
|
|
1506 -- that narrow the predicate choices themselves, so we must
|
|
1507 -- consider only those entries within the range of the given
|
|
1508 -- subtype indication..
|
|
1509
|
|
1510 P := First (Static_Discrete_Predicate (Typ));
|
|
1511 while Present (P) loop
|
|
1512
|
|
1513 -- Check that part of the predicate choice is included in the
|
|
1514 -- given bounds.
|
|
1515
|
|
1516 if Expr_Value (High_Bound (P)) >= Expr_Value (Lo)
|
|
1517 and then Expr_Value (Low_Bound (P)) <= Expr_Value (Hi)
|
|
1518 then
|
|
1519 C := New_Copy (P);
|
|
1520 Set_Sloc (C, Sloc (Choice));
|
|
1521
|
|
1522 if Expr_Value (Low_Bound (C)) < Expr_Value (Lo) then
|
|
1523 Set_Low_Bound (C, Lo);
|
|
1524 end if;
|
|
1525
|
|
1526 if Expr_Value (High_Bound (C)) > Expr_Value (Hi) then
|
|
1527 Set_High_Bound (C, Hi);
|
|
1528 end if;
|
|
1529
|
|
1530 Check (C, Low_Bound (C), High_Bound (C));
|
|
1531 end if;
|
|
1532
|
|
1533 Next (P);
|
|
1534 end loop;
|
|
1535
|
|
1536 Set_Has_SP_Choice (Alt);
|
|
1537 end Handle_Static_Predicate;
|
|
1538
|
|
1539 -- Start of processing for Check_Choices
|
|
1540
|
|
1541 begin
|
|
1542 Raises_CE := False;
|
|
1543 Others_Present := False;
|
|
1544
|
|
1545 -- If Subtyp is not a discrete type or there was some other error,
|
|
1546 -- then don't try any semantic checking on the choices since we have
|
|
1547 -- a complete mess.
|
|
1548
|
|
1549 if not Is_Discrete_Type (Subtyp) or else Subtyp = Any_Type then
|
|
1550 return;
|
|
1551 end if;
|
|
1552
|
|
1553 -- If Subtyp is not a static subtype Ada 95 requires then we use the
|
|
1554 -- bounds of its base type to determine the values covered by the
|
|
1555 -- discrete choices.
|
|
1556
|
|
1557 -- In Ada 2012, if the subtype has a non-static predicate the full
|
|
1558 -- range of the base type must be covered as well.
|
|
1559
|
|
1560 if Is_OK_Static_Subtype (Subtyp) then
|
|
1561 if not Has_Predicates (Subtyp)
|
|
1562 or else Has_Static_Predicate (Subtyp)
|
|
1563 then
|
|
1564 Bounds_Type := Subtyp;
|
|
1565 else
|
|
1566 Bounds_Type := Choice_Type;
|
|
1567 end if;
|
|
1568
|
|
1569 else
|
|
1570 Bounds_Type := Choice_Type;
|
|
1571 end if;
|
|
1572
|
|
1573 -- Obtain static bounds of type, unless this is a generic formal
|
|
1574 -- discrete type for which all choices will be non-static.
|
|
1575
|
|
1576 if not Is_Generic_Type (Root_Type (Bounds_Type))
|
|
1577 or else Ekind (Bounds_Type) /= E_Enumeration_Type
|
|
1578 then
|
|
1579 Bounds_Lo := Expr_Value (Type_Low_Bound (Bounds_Type));
|
|
1580 Bounds_Hi := Expr_Value (Type_High_Bound (Bounds_Type));
|
|
1581 end if;
|
|
1582
|
|
1583 if Choice_Type = Universal_Integer then
|
|
1584 Expected_Type := Any_Integer;
|
|
1585 else
|
|
1586 Expected_Type := Choice_Type;
|
|
1587 end if;
|
|
1588
|
|
1589 -- Now loop through the case alternatives or record variants
|
|
1590
|
|
1591 Alt := First (Alternatives);
|
|
1592 while Present (Alt) loop
|
|
1593
|
|
1594 -- If pragma, just analyze it
|
|
1595
|
|
1596 if Nkind (Alt) = N_Pragma then
|
|
1597 Analyze (Alt);
|
|
1598
|
|
1599 -- Otherwise we have an alternative. In most cases the semantic
|
|
1600 -- processing leaves the list of choices unchanged
|
|
1601
|
|
1602 -- Check each choice against its base type
|
|
1603
|
|
1604 else
|
|
1605 Choice := First (Discrete_Choices (Alt));
|
|
1606 while Present (Choice) loop
|
|
1607 Kind := Nkind (Choice);
|
|
1608
|
|
1609 -- Choice is a Range
|
|
1610
|
|
1611 if Kind = N_Range
|
|
1612 or else (Kind = N_Attribute_Reference
|
|
1613 and then Attribute_Name (Choice) = Name_Range)
|
|
1614 then
|
|
1615 Check (Choice, Low_Bound (Choice), High_Bound (Choice));
|
|
1616
|
|
1617 -- Choice is a subtype name
|
|
1618
|
|
1619 elsif Is_Entity_Name (Choice)
|
|
1620 and then Is_Type (Entity (Choice))
|
|
1621 then
|
|
1622 -- Check for inappropriate type
|
|
1623
|
|
1624 if not Covers (Expected_Type, Etype (Choice)) then
|
|
1625 Wrong_Type (Choice, Choice_Type);
|
|
1626
|
|
1627 -- Type is OK, so check further
|
|
1628
|
|
1629 else
|
|
1630 E := Entity (Choice);
|
|
1631
|
|
1632 -- Case of predicated subtype
|
|
1633
|
|
1634 if Has_Predicates (E) then
|
|
1635
|
|
1636 -- Use of non-static predicate is an error
|
|
1637
|
|
1638 if not Is_Discrete_Type (E)
|
|
1639 or else not Has_Static_Predicate (E)
|
|
1640 or else Has_Dynamic_Predicate_Aspect (E)
|
|
1641 then
|
|
1642 Bad_Predicated_Subtype_Use
|
|
1643 ("cannot use subtype& with non-static "
|
|
1644 & "predicate as case alternative",
|
|
1645 Choice, E, Suggest_Static => True);
|
|
1646
|
|
1647 -- Static predicate case. The bounds are those of
|
|
1648 -- the given subtype.
|
|
1649
|
|
1650 else
|
|
1651 Handle_Static_Predicate (E,
|
|
1652 Type_Low_Bound (E), Type_High_Bound (E));
|
|
1653 end if;
|
|
1654
|
|
1655 -- Not predicated subtype case
|
|
1656
|
|
1657 elsif not Is_OK_Static_Subtype (E) then
|
|
1658 Process_Non_Static_Choice (Choice);
|
|
1659 else
|
|
1660 Check
|
|
1661 (Choice, Type_Low_Bound (E), Type_High_Bound (E));
|
|
1662 end if;
|
|
1663 end if;
|
|
1664
|
|
1665 -- Choice is a subtype indication
|
|
1666
|
|
1667 elsif Kind = N_Subtype_Indication then
|
|
1668 Resolve_Discrete_Subtype_Indication
|
|
1669 (Choice, Expected_Type);
|
|
1670
|
|
1671 if Etype (Choice) /= Any_Type then
|
|
1672 declare
|
|
1673 C : constant Node_Id := Constraint (Choice);
|
|
1674 R : constant Node_Id := Range_Expression (C);
|
|
1675 L : constant Node_Id := Low_Bound (R);
|
|
1676 H : constant Node_Id := High_Bound (R);
|
|
1677
|
|
1678 begin
|
|
1679 E := Entity (Subtype_Mark (Choice));
|
|
1680
|
|
1681 if not Is_OK_Static_Subtype (E) then
|
|
1682 Process_Non_Static_Choice (Choice);
|
|
1683
|
|
1684 else
|
|
1685 if Is_OK_Static_Expression (L)
|
|
1686 and then
|
|
1687 Is_OK_Static_Expression (H)
|
|
1688 then
|
|
1689 if Expr_Value (L) > Expr_Value (H) then
|
|
1690 Process_Empty_Choice (Choice);
|
|
1691 else
|
|
1692 if Is_Out_Of_Range (L, E) then
|
|
1693 Apply_Compile_Time_Constraint_Error
|
|
1694 (L, "static value out of range",
|
|
1695 CE_Range_Check_Failed);
|
|
1696 end if;
|
|
1697
|
|
1698 if Is_Out_Of_Range (H, E) then
|
|
1699 Apply_Compile_Time_Constraint_Error
|
|
1700 (H, "static value out of range",
|
|
1701 CE_Range_Check_Failed);
|
|
1702 end if;
|
|
1703 end if;
|
|
1704 end if;
|
|
1705
|
|
1706 -- Check applicable predicate values within the
|
|
1707 -- bounds of the given range.
|
|
1708
|
|
1709 if Has_Static_Predicate (E) then
|
|
1710 Handle_Static_Predicate (E, L, H);
|
|
1711
|
|
1712 else
|
|
1713 Check (Choice, L, H);
|
|
1714 end if;
|
|
1715 end if;
|
|
1716 end;
|
|
1717 end if;
|
|
1718
|
|
1719 -- The others choice is only allowed for the last
|
|
1720 -- alternative and as its only choice.
|
|
1721
|
|
1722 elsif Kind = N_Others_Choice then
|
|
1723 if not (Choice = First (Discrete_Choices (Alt))
|
|
1724 and then Choice = Last (Discrete_Choices (Alt))
|
|
1725 and then Alt = Last (Alternatives))
|
|
1726 then
|
|
1727 Error_Msg_N
|
|
1728 ("the choice OTHERS must appear alone and last",
|
|
1729 Choice);
|
|
1730 return;
|
|
1731 end if;
|
|
1732
|
|
1733 Others_Present := True;
|
|
1734 Others_Choice := Choice;
|
|
1735
|
|
1736 -- Only other possibility is an expression
|
|
1737
|
|
1738 else
|
|
1739 Check (Choice, Choice, Choice);
|
|
1740 end if;
|
|
1741
|
|
1742 -- Move to next choice
|
|
1743
|
|
1744 Next (Choice);
|
|
1745 end loop;
|
|
1746
|
|
1747 Process_Associated_Node (Alt);
|
|
1748 end if;
|
|
1749
|
|
1750 Next (Alt);
|
|
1751 end loop;
|
|
1752
|
|
1753 -- Now we can create the Choice_Table, since we know how long
|
|
1754 -- it needs to be so we can allocate exactly the right length.
|
|
1755
|
|
1756 declare
|
|
1757 Choice_Table : Choice_Table_Type (0 .. Num_Choices);
|
|
1758
|
|
1759 begin
|
|
1760 -- Now copy the items we collected in the linked list into this
|
|
1761 -- newly allocated table (leave entry 0 unused for sorting).
|
|
1762
|
|
1763 declare
|
|
1764 T : Link_Ptr;
|
|
1765 begin
|
|
1766 for J in 1 .. Num_Choices loop
|
|
1767 T := Choice_List;
|
|
1768 Choice_List := T.Nxt;
|
|
1769 Choice_Table (J) := T.Val;
|
|
1770 Free (T);
|
|
1771 end loop;
|
|
1772 end;
|
|
1773
|
|
1774 Check_Choice_Set
|
|
1775 (Choice_Table,
|
|
1776 Bounds_Type,
|
|
1777 Subtyp,
|
|
1778 Others_Present or else (Choice_Type = Universal_Integer),
|
|
1779 N);
|
|
1780
|
|
1781 -- If no others choice we are all done, otherwise we have one more
|
|
1782 -- step, which is to set the Others_Discrete_Choices field of the
|
|
1783 -- others choice (to contain all otherwise unspecified choices).
|
|
1784 -- Skip this if CE is known to be raised.
|
|
1785
|
|
1786 if Others_Present and not Raises_CE then
|
|
1787 Expand_Others_Choice
|
|
1788 (Case_Table => Choice_Table,
|
|
1789 Others_Choice => Others_Choice,
|
|
1790 Choice_Type => Bounds_Type);
|
|
1791 end if;
|
|
1792 end;
|
|
1793 end Check_Choices;
|
|
1794
|
|
1795 end Generic_Check_Choices;
|
|
1796
|
|
1797 end Sem_Case;
|