gcc/ada/sem_res.ads

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                         GNAT COMPILER COMPONENTS                         --
   4 --                                                                          --
   5 --                              S E M _ R E S                               --
   6 --                                                                          --
   7 --                                 S p e c                                  --
   8 --                                                                          --
   9 --          Copyright (C) 1992-1999 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 2,  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 COPYING.  If not, write --
  19 -- to  the Free Software Foundation,  59 Temple Place - Suite 330,  Boston, --
  20 -- MA 02111-1307, USA.                                                      --
  21 --                                                                          --
  22 -- GNAT was originally developed  by the GNAT team at  New York University. --
  23 -- Extensive contributions were provided by Ada Core Technologies Inc.      --
  24 --                                                                          --
  25 ------------------------------------------------------------------------------
  26
  27 --  Resolution processing for all subexpression nodes. Note that the separate
  28 --  package Sem_Aggr contains the actual resolution routines for aggregates,
  29 --  which are separated off since aggregate processing is complex.
  30
  31 with Snames; use Snames;
  32 with Types;  use Types;
  33
  34 package Sem_Res is
  35
  36    --  As described in Sem_Ch4, the type resolution proceeds in two phases.
  37    --  The first phase is a bottom up pass that is achieved during the
  38    --  recursive traversal performed by the Analyze procedures. This phase
  39    --  determines unambiguous types, and collects sets of possible types
  40    --  where the interpretation is potentially ambiguous.
  41
  42    --  On completing this bottom up pass, which corresponds to a call to
  43    --  Analyze on a complete context, the Resolve routine is called which
  44    --  performs a top down resolution with recursive calls to itself to
  45    --  resolve operands.
  46
  47    --  Since in practice a lot of semantic analysis has to be postponed until
  48    --  types are known (e.g. static folding, setting of suppress flags), the
  49    --  Resolve routines also complete the semantic analyze, and also call the
  50    --  expander for possibly expansion of the completely type resolved node.
  51
  52    procedure Resolve (N : Node_Id; Typ : Entity_Id);
  53    procedure Resolve (N : Node_Id; Typ : Entity_Id; Suppress : Check_Id);
  54    --  Top level type-checking procedure, called in a complete context. The
  55    --  construct N, which is a subexpression, has already been analyzed, and
  56    --  is required to be of type Typ given the analysis of the context (which
  57    --  uses the information gathered on the bottom up phase in Analyze). The
  58    --  resolve routines do various other processing, e.g. static evaluation.
  59    --  If a Suppress argument is present, then the resolution is done with the
  60    --  specified check suppressed (can be All_Checks to suppress all checks).
  61
  62    procedure Resolve_Discrete_Subtype_Indication
  63      (N   : Node_Id;
  64       Typ : Entity_Id);
  65    --  Resolve subtype indications in choices (case statements and
  66    --  aggregates) and in index constraints. Note that the resulting Etype
  67    --  of the subtype indication node is set to the Etype of the contained
  68    --  range (i.e. an Itype is not constructed for the actual subtype).
  69
  70    procedure Resolve_Entry (Entry_Name : Node_Id);
  71    --  Find name of entry being called, and resolve prefix of name with its
  72    --  own type. For now we assume that the prefix cannot be overloaded and
  73    --  the name of the entry plays no role in the resolution.
  74
  75    procedure Analyze_And_Resolve (N : Node_Id);
  76    procedure Analyze_And_Resolve (N : Node_Id; Typ : Entity_Id);
  77    procedure Analyze_And_Resolve
  78      (N        : Node_Id;
  79       Typ      : Entity_Id;
  80       Suppress : Check_Id);
  81    procedure Analyze_And_Resolve
  82      (N        : Node_Id;
  83       Suppress : Check_Id);
  84    --  These routines combine the effect of Analyze and Resolve. If a Suppress
  85    --  argument is present, then the analysis is done with the specified check
  86    --  suppressed (can be All_Checks to suppress all checks). These checks are
  87    --  suppressed for both the analysis and resolution. If the type argument
  88    --  is not present, then the Etype of the expression after the Analyze
  89    --  call is used for the Resolve.
  90
  91    procedure Check_Parameterless_Call (N : Node_Id);
  92    --  Several forms of names can denote calls to entities without para-
  93    --  meters. The context determines whether the name denotes the entity
  94    --  or a call to it. When it is a call, the node must be rebuilt
  95    --  accordingly (deprocedured, in A68 terms) and renalyzed to obtain
  96    --  possible interpretations.
  97    --
  98    --  The name may be that of an overloadable construct, or it can be an
  99    --  explicit dereference of a prefix that denotes an access to subprogram.
 100    --  In that case, we want to convert the name into a call only if the
 101    --  context requires the return type of the subprogram.  Finally, a
 102    --  parameterless protected subprogram appears as a selected component.
 103    --
 104    --  The parameter T is the Typ for the corresponding resolve call.
 105
 106    procedure Pre_Analyze_And_Resolve (N : Node_Id; T : Entity_Id);
 107    --  Performs a pre-analysis of expression node N. During pre-analysis
 108    --  N is analyzed and then resolved against type T, but no expansion
 109    --  is carried out for N or its children. For more info on pre-analysis
 110    --  read the spec of Sem.
 111
 112    procedure Pre_Analyze_And_Resolve (N : Node_Id);
 113    --  Same, but use type of node because context does not impose a single
 114    --  type.
 115
 116 end Sem_Res;