gcc/ada/exp_spark.adb

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                         GNAT COMPILER COMPONENTS                         --
   4 --                                                                          --
   5 --                            E X P _ S P A R K                             --
   6 --                                                                          --
   7 --                                 B o d y                                  --
   8 --                                                                          --
   9 --          Copyright (C) 1992-2015, Free Software Foundation, Inc.         --
  10 --                                                                          --
  11 -- GNAT is free software;  you can  redistribute it  and/or modify it under --
  12 -- terms of the  GNU General Public License as published  by the Free Soft- --
  13 -- ware  Foundation;  either version 3,  or (at your option) any later ver- --
  14 -- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --
  15 -- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
  16 -- or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License --
  17 -- for  more details.  You should have  received  a copy of the GNU General --
  18 -- Public License  distributed with GNAT; see file COPYING3.  If not, go to --
  19 -- http://www.gnu.org/licenses for a complete copy of the license.          --
  20 --                                                                          --
  21 -- GNAT was originally developed  by the GNAT team at  New York University. --
  22 -- Extensive contributions were provided by Ada Core Technologies Inc.      --
  23 --                                                                          --
  24 ------------------------------------------------------------------------------
  25
  26 with Atree;    use Atree;
  27 with Einfo;    use Einfo;
  28 with Exp_Ch5;  use Exp_Ch5;
  29 with Exp_Dbug; use Exp_Dbug;
  30 with Exp_Util; use Exp_Util;
  31 with Sem_Res;  use Sem_Res;
  32 with Sem_Util; use Sem_Util;
  33 with Sinfo;    use Sinfo;
  34
  35 package body Exp_SPARK is
  36
  37    -----------------------
  38    -- Local Subprograms --
  39    -----------------------
  40
  41    procedure Expand_SPARK_N_Object_Renaming_Declaration (N : Node_Id);
  42    --  Perform name evaluation for a renamed object
  43
  44    procedure Expand_Potential_Renaming (N : Node_Id);
  45    --  N denotes a N_Identifier or N_Expanded_Name. If N references a renaming,
  46    --  replace N with the renamed object.
  47
  48    ------------------
  49    -- Expand_SPARK --
  50    ------------------
  51
  52    procedure Expand_SPARK (N : Node_Id) is
  53    begin
  54       case Nkind (N) is
  55
  56          --  Qualification of entity names in formal verification mode
  57          --  is limited to the addition of a suffix for homonyms (see
  58          --  Exp_Dbug.Qualify_Entity_Name). We used to qualify entity names
  59          --  as full expansion does, but this was removed as this prevents the
  60          --  verification back-end from using a short name for debugging and
  61          --  user interaction. The verification back-end already takes care
  62          --  of qualifying names when needed.
  63
  64          when N_Block_Statement     |
  65               N_Package_Body        |
  66               N_Package_Declaration |
  67               N_Subprogram_Body     =>
  68             Qualify_Entity_Names (N);
  69
  70          when N_Expanded_Name |
  71               N_Identifier    =>
  72             Expand_Potential_Renaming (N);
  73
  74          when N_Object_Renaming_Declaration =>
  75             Expand_SPARK_N_Object_Renaming_Declaration (N);
  76
  77          --  Loop iterations over arrays need to be expanded, to avoid getting
  78          --  two names referring to the same object in memory (the array and
  79          --  the iterator) in GNATprove, especially since both can be written
  80          --  (thus possibly leading to interferences due to aliasing). No such
  81          --  problem arises with quantified expressions over arrays, which are
  82          --  dealt with specially in GNATprove.
  83
  84          when N_Loop_Statement =>
  85             declare
  86                Scheme : constant Node_Id := Iteration_Scheme (N);
  87             begin
  88                if Present (Scheme)
  89                  and then Present (Iterator_Specification (Scheme))
  90                  and then
  91                    Is_Iterator_Over_Array (Iterator_Specification (Scheme))
  92                then
  93                   Expand_Iterator_Loop_Over_Array (N);
  94                end if;
  95             end;
  96
  97          --  In SPARK mode, no other constructs require expansion
  98
  99          when others =>
 100             null;
 101       end case;
 102    end Expand_SPARK;
 103
 104    ------------------------------------------------
 105    -- Expand_SPARK_N_Object_Renaming_Declaration --
 106    ------------------------------------------------
 107
 108    procedure Expand_SPARK_N_Object_Renaming_Declaration (N : Node_Id) is
 109    begin
 110       --  Unconditionally remove all side effects from the name
 111
 112       Evaluate_Name (Name (N));
 113    end Expand_SPARK_N_Object_Renaming_Declaration;
 114
 115    -------------------------------
 116    -- Expand_Potential_Renaming --
 117    -------------------------------
 118
 119    procedure Expand_Potential_Renaming (N : Node_Id) is
 120       E : constant Entity_Id := Entity (N);
 121       T : constant Entity_Id := Etype (N);
 122
 123    begin
 124       --  Replace a reference to a renaming with the actual renamed object
 125
 126       if Ekind (E) in Object_Kind and then Present (Renamed_Object (E)) then
 127          Rewrite (N, New_Copy_Tree (Renamed_Object (E)));
 128          Reset_Analyzed_Flags (N);
 129          Analyze_And_Resolve (N, T);
 130       end if;
 131    end Expand_Potential_Renaming;
 132
 133 end Exp_SPARK;