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) 1992-2003 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 Types; use Types;
  32
  33 package Sem_Res is
  34
  35    --  As described in Sem_Ch4, the type resolution proceeds in two phases.
  36    --  The first phase is a bottom up pass that is achieved during the
  37    --  recursive traversal performed by the Analyze procedures. This phase
  38    --  determines unambiguous types, and collects sets of possible types
  39    --  where the interpretation is potentially ambiguous.
  40
  41    --  On completing this bottom up pass, which corresponds to a call to
  42    --  Analyze on a complete context, the Resolve routine is called which
  43    --  performs a top down resolution with recursive calls to itself to
  44    --  resolve operands.
  45
  46    --  Since in practice a lot of semantic analysis has to be postponed until
  47    --  types are known (e.g. static folding, setting of suppress flags), the
  48    --  Resolve routines also complete the semantic analysis, and call the
  49    --  expander for possibly expansion of the completely type resolved node.
  50
  51    procedure Resolve (N : Node_Id; Typ : Entity_Id);
  52    procedure Resolve (N : Node_Id; Typ : Entity_Id; Suppress : Check_Id);
  53    --  Top level type-checking procedure, called in a complete context. The
  54    --  construct N, which is a subexpression, has already been analyzed, and
  55    --  is required to be of type Typ given the analysis of the context (which
  56    --  uses the information gathered on the bottom up phase in Analyze). The
  57    --  resolve routines do various other processing, e.g. static evaluation.
  58    --  If a Suppress argument is present, then the resolution is done with the
  59    --  specified check suppressed (can be All_Checks to suppress all checks).
  60
  61    procedure Resolve (N : Node_Id);
  62    pragma Inline (Resolve);
  63    --  A version of Resolve where the type to be used for resolution is
  64    --  taken from the Etype (N). This is commonly used in cases where the
  65    --  context does not add anything and the first pass of analysis found
  66    --  the correct expected type.
  67
  68    procedure Resolve_Discrete_Subtype_Indication
  69      (N   : Node_Id;
  70       Typ : Entity_Id);
  71    --  Resolve subtype indications in choices (case statements and
  72    --  aggregates) and in index constraints. Note that the resulting Etype
  73    --  of the subtype indication node is set to the Etype of the contained
  74    --  range (i.e. an Itype is not constructed for the actual subtype).
  75
  76    procedure Resolve_Entry (Entry_Name : Node_Id);
  77    --  Find name of entry being called, and resolve prefix of name with its
  78    --  own type. For now we assume that the prefix cannot be overloaded and
  79    --  the name of the entry plays no role in the resolution.
  80
  81    procedure Analyze_And_Resolve (N : Node_Id);
  82    procedure Analyze_And_Resolve (N : Node_Id; Typ : Entity_Id);
  83    procedure Analyze_And_Resolve
  84      (N        : Node_Id;
  85       Typ      : Entity_Id;
  86       Suppress : Check_Id);
  87    procedure Analyze_And_Resolve
  88      (N        : Node_Id;
  89       Suppress : Check_Id);
  90    --  These routines combine the effect of Analyze and Resolve. If a Suppress
  91    --  argument is present, then the analysis is done with the specified check
  92    --  suppressed (can be All_Checks to suppress all checks). These checks are
  93    --  suppressed for both the analysis and resolution. If the type argument
  94    --  is not present, then the Etype of the expression after the Analyze
  95    --  call is used for the Resolve.
  96
  97    procedure Check_Parameterless_Call (N : Node_Id);
  98    --  Several forms of names can denote calls to entities without para-
  99    --  meters. The context determines whether the name denotes the entity
 100    --  or a call to it. When it is a call, the node must be rebuilt
 101    --  accordingly and renalyzed to obtain possible interpretations.
 102    --
 103    --  The name may be that of an overloadable construct, or it can be an
 104    --  explicit dereference of a prefix that denotes an access to subprogram.
 105    --  In that case, we want to convert the name into a call only if the
 106    --  context requires the return type of the subprogram.  Finally, a
 107    --  parameterless protected subprogram appears as a selected component.
 108    --
 109    --  The parameter T is the Typ for the corresponding resolve call.
 110
 111    procedure Pre_Analyze_And_Resolve (N : Node_Id; T : Entity_Id);
 112    --  Performs a pre-analysis of expression node N. During pre-analysis
 113    --  N is analyzed and then resolved against type T, but no expansion
 114    --  is carried out for N or its children. For more info on pre-analysis
 115    --  read the spec of Sem.
 116
 117    procedure Pre_Analyze_And_Resolve (N : Node_Id);
 118    --  Same, but use type of node because context does not impose a single
 119    --  type.
 120
 121 end Sem_Res;