1 ------------------------------------------------------------------------------
3 -- GNAT COMPILER COMPONENTS --
5 -- S Y S T E M . S T A N D A R D _ L I B R A R Y --
9 -- Copyright (C) 1992-2023, Free Software Foundation, Inc. --
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. --
18 -- As a special exception under Section 7 of GPL version 3, you are granted --
19 -- additional permissions described in the GCC Runtime Library Exception, --
20 -- version 3.1, as published by the Free Software Foundation. --
22 -- You should have received a copy of the GNU General Public License and --
23 -- a copy of the GCC Runtime Library Exception along with this program; --
24 -- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see --
25 -- <http://www.gnu.org/licenses/>. --
27 -- GNAT was originally developed by the GNAT team at New York University. --
28 -- Extensive contributions were provided by Ada Core Technologies Inc. --
30 ------------------------------------------------------------------------------
32 -- This package is included in all programs. It contains declarations that
33 -- are required to be part of every Ada program. A special mechanism is
34 -- required to ensure that these are loaded, since it may be the case in
35 -- some programs that the only references to these required packages are
36 -- from C code or from code generated directly by Gigi, and in both cases
37 -- the binder is not aware of such references.
39 -- System.Standard_Library also includes data that must be present in every
40 -- program, in particular data for all the standard exceptions, and also some
41 -- subprograms that must be present in every program.
43 -- The binder unconditionally includes s-stalib.ali, which ensures that this
44 -- package and the packages it references are included in all Ada programs,
45 -- together with the included data.
47 with Ada
.Unchecked_Conversion
;
49 package System
.Standard_Library
is
51 -- Historical note: pragma Preelaborate was surrounded by a pair of pragma
52 -- Warnings (Off/On) to circumvent a bootstrap issue.
56 subtype Big_String
is String (1 .. Positive'Last);
57 pragma Suppress_Initialization
(Big_String
);
58 -- Type used to obtain string access to given address. Initialization is
59 -- suppressed, since we never want to have variables of this type, and
60 -- we never want to attempt initialiazation of virtual variables of this
61 -- type (e.g. when pragma Normalize_Scalars is used).
63 type Big_String_Ptr
is access all Big_String
;
64 for Big_String_Ptr
'Storage_Size use 0;
65 -- We use this access type to pass a pointer to an area of storage to be
66 -- accessed as a string. Of course when this pointer is used, it is the
67 -- responsibility of the accessor to ensure proper bounds. The storage
68 -- size clause ensures we do not allocate variables of this type.
71 new Ada
.Unchecked_Conversion
(System
.Address
, Big_String_Ptr
);
73 -------------------------------------
74 -- Exception Declarations and Data --
75 -------------------------------------
77 type Raise_Action
is access procedure;
78 pragma Favor_Top_Level
(Raise_Action
);
79 -- A pointer to a procedure used in the Raise_Hook field
82 type Exception_Data_Ptr
is access all Exception_Data
;
83 -- An equivalent of Exception_Id that is public
85 -- The following record defines the underlying representation of exceptions
87 -- WARNING: Any change to the record needs to be reflected in the following
88 -- locations in the compiler and runtime code:
90 -- 1. The construction of the exception type in Cstand
91 -- 2. Expand_N_Exception_Declaration in Exp_Ch11
92 -- 3. Expand_Pragma_Import_Or_Interface in Exp_Prag
93 -- 4. The processing in gigi that tests Not_Handled_By_Others
94 -- 5. The Internal_Exception routine in s-exctab.adb
95 -- 6. The declaration of the corresponding C type in raise.h
97 type Exception_Data
is record
98 Not_Handled_By_Others
: aliased Boolean;
99 -- Normally set False, indicating that the exception is handled in the
100 -- usual way by others (i.e. an others handler handles the exception).
101 -- Set True to indicate that this exception is not caught by others
102 -- handlers, but must be explicitly named in a handler. This latter
103 -- setting is currently used by the Abort_Signal.
105 Lang
: aliased Character;
106 -- A character indicating the language raising the exception.
107 -- Set to "A" for exceptions defined by an Ada program.
108 -- Set to "C" for imported C++ exceptions.
110 Name_Length
: aliased Natural;
111 -- Length of fully expanded name of exception
113 Full_Name
: aliased System
.Address
;
114 -- Fully expanded name of exception, null terminated
115 -- You can use To_Ptr to convert this to a string.
117 HTable_Ptr
: aliased Exception_Data_Ptr
;
118 -- Hash table pointer used to link entries together in the hash table
119 -- built (by Register_Exception in s-exctab.adb) for converting between
120 -- identities and names.
122 Foreign_Data
: aliased System
.Address
;
123 -- Data for imported exceptions. Not used in the Ada case. This
124 -- represents the address of the RTTI for the C++ case.
126 Raise_Hook
: aliased Raise_Action
;
127 -- This field can be used to place a "hook" on an exception. If the
128 -- value is non-null, then it points to a procedure which is called
129 -- whenever the exception is raised. This call occurs immediately,
130 -- before any other actions taken by the raise (and in particular
131 -- before any unwinding of the stack occurs).
134 -- Definitions for standard predefined exceptions defined in Standard,
136 -- Why are the NULs necessary here, seems like they should not be
137 -- required, since Gigi is supposed to add a Nul to each name ???
139 Constraint_Error_Name
: constant String := "CONSTRAINT_ERROR" & ASCII
.NUL
;
140 Program_Error_Name
: constant String := "PROGRAM_ERROR" & ASCII
.NUL
;
141 Storage_Error_Name
: constant String := "STORAGE_ERROR" & ASCII
.NUL
;
142 Tasking_Error_Name
: constant String := "TASKING_ERROR" & ASCII
.NUL
;
143 Abort_Signal_Name
: constant String := "_ABORT_SIGNAL" & ASCII
.NUL
;
145 Numeric_Error_Name
: constant String := "NUMERIC_ERROR" & ASCII
.NUL
;
146 -- This is used only in the Ada 83 case, but it is not worth having a
147 -- separate version of s-stalib.ads for use in Ada 83 mode.
149 Constraint_Error_Def
: aliased Exception_Data
:=
150 (Not_Handled_By_Others
=> False,
152 Name_Length
=> Constraint_Error_Name
'Length,
153 Full_Name
=> Constraint_Error_Name
'Address,
155 Foreign_Data
=> Null_Address
,
158 Numeric_Error_Def
: aliased Exception_Data
:=
159 (Not_Handled_By_Others
=> False,
161 Name_Length
=> Numeric_Error_Name
'Length,
162 Full_Name
=> Numeric_Error_Name
'Address,
164 Foreign_Data
=> Null_Address
,
167 Program_Error_Def
: aliased Exception_Data
:=
168 (Not_Handled_By_Others
=> False,
170 Name_Length
=> Program_Error_Name
'Length,
171 Full_Name
=> Program_Error_Name
'Address,
173 Foreign_Data
=> Null_Address
,
176 Storage_Error_Def
: aliased Exception_Data
:=
177 (Not_Handled_By_Others
=> False,
179 Name_Length
=> Storage_Error_Name
'Length,
180 Full_Name
=> Storage_Error_Name
'Address,
182 Foreign_Data
=> Null_Address
,
185 Tasking_Error_Def
: aliased Exception_Data
:=
186 (Not_Handled_By_Others
=> False,
188 Name_Length
=> Tasking_Error_Name
'Length,
189 Full_Name
=> Tasking_Error_Name
'Address,
191 Foreign_Data
=> Null_Address
,
194 Abort_Signal_Def
: aliased Exception_Data
:=
195 (Not_Handled_By_Others
=> True,
197 Name_Length
=> Abort_Signal_Name
'Length,
198 Full_Name
=> Abort_Signal_Name
'Address,
200 Foreign_Data
=> Null_Address
,
203 pragma Export
(C
, Constraint_Error_Def
, "constraint_error");
204 pragma Export
(C
, Numeric_Error_Def
, "numeric_error");
205 pragma Export
(C
, Program_Error_Def
, "program_error");
206 pragma Export
(C
, Storage_Error_Def
, "storage_error");
207 pragma Export
(C
, Tasking_Error_Def
, "tasking_error");
208 pragma Export
(C
, Abort_Signal_Def
, "_abort_signal");
210 Local_Partition_ID
: Natural := 0;
211 -- This variable contains the local Partition_ID that will be used when
212 -- building exception occurrences. In distributed mode, it will be
213 -- set by each partition to the correct value during the elaboration.
215 type Exception_Trace_Kind
is
217 -- No particular trace is requested, only unhandled exceptions
218 -- in the environment task (following the RM) will be printed.
219 -- This is the default behavior.
222 -- Denotes the initial raise event for any exception occurrence, either
223 -- explicit or due to a specific language rule, within the context of a
227 -- Denotes the raise events corresponding to exceptions for which there
228 -- is no user defined handler. This includes unhandled exceptions in
231 Unhandled_Raise_In_Main
232 -- Same as Unhandled_Raise, except exceptions in task bodies are not
233 -- included. Same as RM_Convention, except (1) the message is printed as
234 -- soon as the environment task completes due to an unhandled exception
235 -- (before awaiting the termination of dependent tasks, and before
236 -- library-level finalization), and (2) a symbolic traceback is given
237 -- if possible. This is the default behavior if the binder switch -E is
240 -- Provide a way to denote different kinds of automatic traces related
241 -- to exceptions that can be requested.
243 Exception_Trace
: Exception_Trace_Kind
:= RM_Convention
;
244 pragma Atomic
(Exception_Trace
);
245 -- By default, follow the RM convention
251 procedure Abort_Undefer_Direct
;
252 pragma Inline
(Abort_Undefer_Direct
);
253 -- A little procedure that just calls Abort_Undefer.all, for use in
254 -- clean up procedures, which only permit a simple subprogram name.
257 -- Performs the Ada Runtime finalization the first time it is invoked.
258 -- All subsequent calls are ignored.
260 end System
.Standard_Library
;