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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 H 8 --
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6 -- --
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7 -- S p e c --
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8 -- --
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131
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9 -- Copyright (C) 1992-2018, 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 Types; use Types;
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27 package Sem_Ch8 is
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28
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29 -----------------------------------
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30 -- Handling extensions of System --
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31 -----------------------------------
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32
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33 -- For targets that define a much larger System package than given in
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34 -- the RM, we use a child package containing additional declarations,
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35 -- which is loaded when needed, and whose entities are conceptually
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36 -- within System itself. The presence of this auxiliary package is
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37 -- controlled with the pragma Extend_System. The following variable
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38 -- holds the entity of the auxiliary package, to simplify the special
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39 -- visibility rules that apply to it.
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40
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41 System_Aux_Id : Entity_Id := Empty;
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42
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43 -----------------
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44 -- Subprograms --
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45 -----------------
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46
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47 procedure Analyze_Exception_Renaming (N : Node_Id);
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48 procedure Analyze_Expanded_Name (N : Node_Id);
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49 procedure Analyze_Generic_Function_Renaming (N : Node_Id);
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50 procedure Analyze_Generic_Package_Renaming (N : Node_Id);
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51 procedure Analyze_Generic_Procedure_Renaming (N : Node_Id);
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52 procedure Analyze_Object_Renaming (N : Node_Id);
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53 procedure Analyze_Package_Renaming (N : Node_Id);
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54 procedure Analyze_Subprogram_Renaming (N : Node_Id);
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55
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56 procedure Analyze_Use_Package (N : Node_Id; Chain : Boolean := True);
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57 -- Analyze a use package clause and control (through the Chain parameter)
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58 -- whether to add N to the use clause chain for the name denoted within
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59 -- use clause N in case we are reanalyzing a use clause because of stack
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60 -- manipulation.
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61
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62 procedure Analyze_Use_Type (N : Node_Id; Chain : Boolean := True);
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63 -- Similar to Analyze_Use_Package except the Chain parameter applies to the
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64 -- type within N's subtype mark Current_Use_Clause.
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65
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66 procedure End_Scope;
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67 -- Called at end of scope. On exit from blocks and bodies (subprogram,
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68 -- package, task, and protected bodies), the name of the current scope
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69 -- must be removed from the scope stack, and the local entities must be
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70 -- removed from their homonym chains. On exit from record declarations,
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71 -- from package specifications, and from tasks and protected type
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72 -- specifications, more specialized procedures are invoked.
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73
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74 procedure End_Use_Clauses (Clause : Node_Id);
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75 -- Invoked on scope exit, to undo the effect of local use clauses. Clause
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76 -- is the first use-clause of a scope being exited. This can be the current
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77 -- scope, or some enclosing scopes when building a clean environment to
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78 -- compile an instance body for inlining.
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79
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80 procedure End_Use_Package (N : Node_Id);
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81 procedure End_Use_Type (N : Node_Id);
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82 -- Subsidiaries of End_Use_Clauses. Also called directly for use clauses
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83 -- appearing in context clauses.
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84
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85 procedure Find_Direct_Name (N : Node_Id);
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86 -- Given a direct name (Identifier or Operator_Symbol), this routine scans
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87 -- the homonym chain for the name, searching for corresponding visible
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88 -- entities to find the referenced entity (or in the case of overloading,
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89 -- one candidate interpretation). On return, the Entity and Etype fields
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90 -- are set. In the non-overloaded case, these are the correct entries.
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91 -- In the overloaded case, the flag Is_Overloaded is set, Etype and Entity
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92 -- refer to an arbitrary element of the overloads set, and the appropriate
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93 -- entries have been added to the overloads table entry for the node. The
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94 -- overloading will be disambiguated during type resolution.
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95 --
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96 -- Note, when this is called during semantic analysis in the overloaded
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97 -- case, the entity set will be the most recently declared homonym. In
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98 -- particular, the caller may follow the homonym chain checking for all
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99 -- entries in the current scope, and that will give all homonyms that are
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100 -- declared before the point of call in the current scope. This is useful
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101 -- for example in the processing for pragma Inline.
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102
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103 procedure Find_Selected_Component (N : Node_Id);
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104 -- Resolve various cases of selected components, recognize expanded names
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105
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106 procedure Find_Type (N : Node_Id);
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107 -- Perform name resolution, and verify that the name found is that of a
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108 -- type. On return the Entity and Etype fields of the node N are set
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109 -- appropriately. If it is an incomplete type whose full declaration has
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110 -- been seen, they are set to the entity in the full declaration. If it
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111 -- is an incomplete type associated with an interface visible through a
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112 -- limited-with clause, whose full declaration has been seen, they are
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113 -- set to the entity in the full declaration. Similarly, if the type is
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114 -- private, it has received a full declaration, and we are in the private
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115 -- part or body of the package, then the two fields are set to the entity
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116 -- of the full declaration as well. This procedure also has special
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117 -- processing for 'Class attribute references.
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118
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119 function Has_Loop_In_Inner_Open_Scopes (S : Entity_Id) return Boolean;
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120 -- S is the entity of an open scope. This function determines if there is
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121 -- an inner scope of S which is a loop (i.e. it appears somewhere in the
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122 -- scope stack after S).
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123
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124 function In_Open_Scopes (S : Entity_Id) return Boolean;
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125 -- S is the entity of a scope. This function determines if this scope is
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126 -- currently open (i.e. it appears somewhere in the scope stack).
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127
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128 procedure Initialize;
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129 -- Initializes data structures used for visibility analysis. Must be
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130 -- called before analyzing each new main source program.
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131
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132 procedure Install_Use_Clauses
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133 (Clause : Node_Id;
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134 Force_Installation : Boolean := False);
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135 -- Applies the use clauses appearing in a given declarative part,
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136 -- when the corresponding scope has been placed back on the scope
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137 -- stack after unstacking to compile a different context (subunit or
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138 -- parent of generic body). Force_Installation is used when called from
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139 -- Analyze_Subunit.Re_Install_Use_Clauses to insure that, after the
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140 -- analysis of the subunit, the parent's environment is again identical.
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141
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142 procedure Mark_Use_Clauses (Id : Node_Or_Entity_Id);
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143 -- Mark a given entity or node Id's relevant use clauses as effective,
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144 -- including redundant ones and ones outside of the current scope.
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145
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146 procedure Push_Scope (S : Entity_Id);
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147 -- Make new scope stack entry, pushing S, the entity for a scope onto the
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148 -- top of the scope table. The current setting of the scope suppress flags
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149 -- is saved for restoration on exit.
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150
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151 procedure Pop_Scope;
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152 -- Remove top entry from scope stack, restoring the saved setting of the
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153 -- scope suppress flags.
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154
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155 function Present_System_Aux (N : Node_Id := Empty) return Boolean;
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156 -- Return True if the auxiliary system file has been successfully loaded.
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157 -- Otherwise attempt to load it, using the name supplied by a previous
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158 -- Extend_System pragma, and report on the success of the load. If N is
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159 -- present, it is a selected component whose prefix is System, or else a
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160 -- with-clause on system. N is absent when the function is called to find
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161 -- the visibility of implicit operators.
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162
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163 function Save_Scope_Stack
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164 (Handle_Use : Boolean := True) return Elist_Id;
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165 procedure Restore_Scope_Stack
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166 (List : Elist_Id;
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167 Handle_Use : Boolean := True);
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168 -- These two subprograms are called from Semantics, when a unit U1 is to
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169 -- be compiled in the course of the compilation of another unit U2. This
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170 -- happens whenever Rtsfind is called. U1, the unit retrieved by Rtsfind,
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171 -- must be compiled in its own context, and the current scope stack
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172 -- containing U2 and local scopes must be made unreachable. This is
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173 -- achieved using a call to Save_Scope_Stack. On return, the contents
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174 -- of the scope stack must be made accessible again with a call to
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175 -- Restore_Scope_Stack.
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176 --
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177 -- The flag Handle_Use indicates whether local use clauses must be removed
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178 -- or installed. In the case of inlining of instance bodies, the visibility
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179 -- handling is done fully in Inline_Instance_Body, and use clauses are
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180 -- handled there. Save_Scope_Stack returns the list of entities which have
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181 -- been temporarily removed from visibility; that list must be passed to
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182 -- Restore_Scope_Stack to restore their visibility.
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183
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184 procedure Set_Use (L : List_Id);
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185 -- Find use clauses that are declarative items in a package declaration
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186 -- and set the potentially use-visible flags of imported entities before
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187 -- analyzing the corresponding package body.
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188
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189 procedure Update_Use_Clause_Chain;
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190 -- Called at the end of a declarative region to detect unused use type
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191 -- clauses and maintain the Current_Use_Clause for type entities.
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192
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193 procedure ws;
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194 -- Debugging routine for use in gdb: dump all entities on scope stack
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195
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196 procedure we (S : Entity_Id);
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197 -- Debugging routine for use in gdb: dump all entities in given scope
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198
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199 end Sem_Ch8;
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