1------------------------------------------------------------------------------
2--                                                                          --
3--                         GNAT COMPILER COMPONENTS                         --
4--                                                                          --
5--                              V A L I D S W                               --
6--                                                                          --
7--                                 S p e c                                  --
8--                                                                          --
9--          Copyright (C) 2001-2012, 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--  This unit contains the routines used to handle setting of validity
27--  checking options.
28
29package Validsw is
30
31   -----------------------------
32   -- Validity Check Switches --
33   -----------------------------
34
35   --  The following flags determine the specific set of validity checks
36   --  to be made if validity checking is active (Validity_Checks_On = True)
37
38   --  See GNAT users guide for an exact description of each option. The letter
39   --  given in the comment is the letter used in the -gnatV compiler switch
40   --  or in the argument of a Validity_Checks pragma to activate the option.
41   --  The corresponding upper case letter deactivates the option.
42
43   Validity_Check_Copies : Boolean := False;
44   --  Controls the validity checking of copies. If this switch is set to
45   --  true using -gnatVc, or a 'c' in the argument of a Validity_Checks
46   --  pragma, then the right side of assignments and also initializing
47   --  expressions in object declarations are checked for validity.
48
49   Validity_Check_Components : Boolean := False;
50   --  Controls validity checking for assignment to elementary components of
51   --  records. If this switch is set true using -gnatVe, or an 'e' in the
52   --  argument of Validity_Checks pragma, then the right hand of an assignment
53   --  to such a component is checked for validity.
54
55   Validity_Check_Default : Boolean := True;
56   --  Controls default (reference manual) validity checking. If this switch is
57   --  set to True using -gnatVd or a 'd' in the argument of a Validity_ Checks
58   --  pragma (or the initial default value is used, set True), then left side
59   --  subscripts and case statement arguments are checked for validity. This
60   --  switch is also set by default if no -gnatV switch is used and no
61   --  Validity_Checks pragma is processed.
62
63   Validity_Check_Floating_Point : Boolean := False;
64   --  Normally validity checking applies only to discrete values (integer
65   --  and enumeration types). If this switch is set to True using -gnatVf
66   --  or an 'f' in the argument of a Validity_Checks pragma, then floating-
67   --  point values are also checked. The context in which such checks
68   --  occur depends on other flags, e.g. if Validity_Check_Copies is also
69   --  set then floating-point values on the right side of an assignment
70   --  will be validity checked.
71
72   Validity_Check_In_Out_Params : Boolean := False;
73   --  Controls the validity checking of IN OUT parameters. If this switch
74   --  is set to True using -gnatVm or a 'm' in the argument of a pragma
75   --  Validity_Checks, then the initial value of all IN OUT parameters
76   --  will be checked at the point of call of a procedure. Note that the
77   --  character 'm' here stands for modified (parameters).
78
79   Validity_Check_In_Params : Boolean := False;
80   --  Controls the validity checking of IN parameters. If this switch is
81   --  set to True using -gnatVi or an 'i' in the argument of a pragma
82   --  Validity_Checks, then the initial value of all IN parameters
83   --  will be checked at the point of call of a procedure or function.
84
85   Validity_Check_Operands : Boolean := False;
86   --  Controls validity checking of operands. If this switch is set to
87   --  True using -gnatVo or an 'o' in the argument of a Validity_Checks
88   --  pragma, then operands of all predefined operators and attributes
89   --  will be validity checked.
90
91   Validity_Check_Parameters : Boolean := False;
92   --  This controls validity treatment for parameters within a subprogram.
93   --  Normally if validity checking is enabled for parameters on a call
94   --  (Validity_Check_In[_Out]_Params) then an assumption is made that the
95   --  parameter values are valid on entry and not checked again within a
96   --  procedure. Setting Validity_Check_Parameters removes this assumption
97   --  and ensures that no assumptions are made about parameters, so that
98   --  they will always be checked.
99
100   Validity_Check_Returns : Boolean := False;
101   --  Controls validity checking of returned values. If this switch is set
102   --  to True using -gnatVr, or an 'r' in the argument of a Validity_Checks
103   --  pragma, then the expression in a RETURN statement is validity checked.
104
105   Validity_Check_Subscripts : Boolean := False;
106   --  Controls validity checking of subscripts. If this switch is set to
107   --  True using -gnatVs, or an 's' in the argument of a Validity_Checks
108   --  pragma, then all subscripts are checked for validity. Note that left
109   --  side subscript checking is controlled also by Validity_Check_Default.
110   --  If Validity_Check_Subscripts is True, then all subscripts are checked,
111   --  otherwise if Validity_Check_Default is True, then left side subscripts
112   --  are checked, otherwise no subscripts are checked.
113
114   Validity_Check_Tests : Boolean := False;
115   --  Controls validity checking of tests that occur in conditions (i.e. the
116   --  tests in IF, WHILE, and EXIT statements, and in entry guards). If this
117   --  switch is set to True using -gnatVt, or a 't' in the argument of a
118   --  Validity_Checks pragma, then all such conditions are validity checked.
119
120   Force_Validity_Checks : Boolean := False;
121   --  Normally, operands that do not come from source (i.e. cases of expander
122   --  generated code) are not checked, if this flag is set True, then checking
123   --  of such operands is forced (if Validity_Check_Operands is set).
124
125   -----------------
126   -- Subprograms --
127   -----------------
128
129   procedure Set_Default_Validity_Check_Options;
130   --  This procedure is called to set the default validity checking options
131   --  that apply if no Validity_Check switches or pragma is given.
132
133   procedure Set_Validity_Check_Options
134     (Options  : String;
135      OK       : out Boolean;
136      Err_Col  : out Natural);
137   --  This procedure is called to set the validity check options that
138   --  correspond to the characters in the given Options string. If
139   --  all options are valid, then Set_Default_Validity_Check_Options
140   --  is first called to set the defaults, and then the options in the
141   --  given string are set in an additive manner. If any invalid character
142   --  is found, then OK is False on exit, and Err_Col is the index in
143   --  in options of the bad character. If all options are valid, then
144   --  OK is True on return, and Err_Col is set to options'Last + 1.
145
146   procedure Set_Validity_Check_Options (Options : String);
147   --  Like the above procedure, except that the call is simply ignored if
148   --  there are any error conditions, this is for example appropriate for
149   --  calls where the string is known to be valid, e.g. because it was
150   --  obtained by Save_Validity_Check_Options.
151
152   procedure Reset_Validity_Check_Options;
153   --  Sets all validity check options to off
154
155   subtype Validity_Check_Options is String (1 .. 16);
156   --  Long enough string to hold all options from Save call below
157
158   procedure Save_Validity_Check_Options
159     (Options : out Validity_Check_Options);
160   --  Sets Options to represent current selection of options. This
161   --  set can be restored by first calling Reset_Validity_Check_Options,
162   --  and then calling Set_Validity_Check_Options with the Options string.
163
164end Validsw;
165