1------------------------------------------------------------------------------ 2-- -- 3-- GNAT RUN-TIME COMPONENTS -- 4-- -- 5-- A D A . E X C E P T I O N S -- 6-- -- 7-- S p e c -- 8-- -- 9-- Copyright (C) 1992-2020, Free Software Foundation, Inc. -- 10-- -- 11-- This specification is derived from the Ada Reference Manual for use with -- 12-- GNAT. The copyright notice above, and the license provisions that follow -- 13-- apply solely to the contents of the part following the private keyword. -- 14-- -- 15-- GNAT is free software; you can redistribute it and/or modify it under -- 16-- terms of the GNU General Public License as published by the Free Soft- -- 17-- ware Foundation; either version 3, or (at your option) any later ver- -- 18-- sion. GNAT is distributed in the hope that it will be useful, but WITH- -- 19-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY -- 20-- or FITNESS FOR A PARTICULAR PURPOSE. -- 21-- -- 22-- As a special exception under Section 7 of GPL version 3, you are granted -- 23-- additional permissions described in the GCC Runtime Library Exception, -- 24-- version 3.1, as published by the Free Software Foundation. -- 25-- -- 26-- You should have received a copy of the GNU General Public License and -- 27-- a copy of the GCC Runtime Library Exception along with this program; -- 28-- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see -- 29-- <http://www.gnu.org/licenses/>. -- 30-- -- 31-- GNAT was originally developed by the GNAT team at New York University. -- 32-- Extensive contributions were provided by Ada Core Technologies Inc. -- 33-- -- 34------------------------------------------------------------------------------ 35 36-- This is the default version of this package. We also have cert and zfp 37-- versions. 38 39with System; 40with System.Parameters; 41with System.Standard_Library; 42with System.Traceback_Entries; 43 44package Ada.Exceptions is 45 pragma Preelaborate; 46 -- In accordance with Ada 2005 AI-362. 47 48 type Exception_Id is private; 49 pragma Preelaborable_Initialization (Exception_Id); 50 51 Null_Id : constant Exception_Id; 52 53 type Exception_Occurrence is limited private; 54 pragma Preelaborable_Initialization (Exception_Occurrence); 55 56 type Exception_Occurrence_Access is access all Exception_Occurrence; 57 58 Null_Occurrence : constant Exception_Occurrence; 59 60 function Exception_Name (Id : Exception_Id) return String; 61 62 function Exception_Name (X : Exception_Occurrence) return String; 63 64 function Wide_Exception_Name 65 (Id : Exception_Id) return Wide_String; 66 pragma Ada_05 (Wide_Exception_Name); 67 68 function Wide_Exception_Name 69 (X : Exception_Occurrence) return Wide_String; 70 pragma Ada_05 (Wide_Exception_Name); 71 72 function Wide_Wide_Exception_Name 73 (Id : Exception_Id) return Wide_Wide_String; 74 pragma Ada_05 (Wide_Wide_Exception_Name); 75 76 function Wide_Wide_Exception_Name 77 (X : Exception_Occurrence) return Wide_Wide_String; 78 pragma Ada_05 (Wide_Wide_Exception_Name); 79 80 procedure Raise_Exception (E : Exception_Id; Message : String := ""); 81 pragma No_Return (Raise_Exception); 82 -- Note: In accordance with AI-466, CE is raised if E = Null_Id 83 84 function Exception_Message (X : Exception_Occurrence) return String; 85 86 procedure Reraise_Occurrence (X : Exception_Occurrence); 87 -- Note: it would be really nice to give a pragma No_Return for this 88 -- procedure, but it would be wrong, since Reraise_Occurrence does return 89 -- if the argument is the null exception occurrence. See also procedure 90 -- Reraise_Occurrence_Always in the private part of this package. 91 92 function Exception_Identity (X : Exception_Occurrence) return Exception_Id; 93 94 function Exception_Information (X : Exception_Occurrence) return String; 95 -- The format of the exception information is as follows: 96 -- 97 -- exception name (as in Exception_Name) 98 -- message (or a null line if no message) 99 -- PID=nnnn 100 -- 0xyyyyyyyy 0xyyyyyyyy ... 101 -- 102 -- The lines are separated by a ASCII.LF character 103 -- 104 -- The nnnn is the partition Id given as decimal digits 105 -- 106 -- The 0x... line represents traceback program counter locations, 107 -- in order with the first one being the exception location. 108 109 -- Note on ordering: the compiler uses the Save_Occurrence procedure, but 110 -- not the function from Rtsfind, so it is important that the procedure 111 -- come first, since Rtsfind finds the first matching entity. 112 113 procedure Save_Occurrence 114 (Target : out Exception_Occurrence; 115 Source : Exception_Occurrence); 116 117 function Save_Occurrence 118 (Source : Exception_Occurrence) 119 return Exception_Occurrence_Access; 120 121 -- Ada 2005 (AI-438): The language revision introduces the following 122 -- subprograms and attribute definitions. We do not provide them 123 -- explicitly. instead, the corresponding stream attributes are made 124 -- available through a pragma Stream_Convert in the private part. 125 126 -- procedure Read_Exception_Occurrence 127 -- (Stream : not null access Ada.Streams.Root_Stream_Type'Class; 128 -- Item : out Exception_Occurrence); 129 130 -- procedure Write_Exception_Occurrence 131 -- (Stream : not null access Ada.Streams.Root_Stream_Type'Class; 132 -- Item : Exception_Occurrence); 133 134 -- for Exception_Occurrence'Read use Read_Exception_Occurrence; 135 -- for Exception_Occurrence'Write use Write_Exception_Occurrence; 136 137private 138 package SSL renames System.Standard_Library; 139 package SP renames System.Parameters; 140 141 subtype EOA is Exception_Occurrence_Access; 142 143 Exception_Msg_Max_Length : constant := SP.Default_Exception_Msg_Max_Length; 144 145 ------------------ 146 -- Exception_Id -- 147 ------------------ 148 149 subtype Code_Loc is System.Address; 150 -- Code location used in building exception tables and for call addresses 151 -- when propagating an exception. Values of this type are created by using 152 -- Label'Address or extracted from machine states using Get_Code_Loc. 153 154 Null_Loc : constant Code_Loc := System.Null_Address; 155 -- Null code location, used to flag outer level frame 156 157 type Exception_Id is new SSL.Exception_Data_Ptr; 158 159 function EId_To_String (X : Exception_Id) return String; 160 function String_To_EId (S : String) return Exception_Id; 161 pragma Stream_Convert (Exception_Id, String_To_EId, EId_To_String); 162 -- Functions for implementing Exception_Id stream attributes 163 164 Null_Id : constant Exception_Id := null; 165 166 ------------------------- 167 -- Private Subprograms -- 168 ------------------------- 169 170 function Exception_Name_Simple (X : Exception_Occurrence) return String; 171 -- Like Exception_Name, but returns the simple non-qualified name of the 172 -- exception. This is used to implement the Exception_Name function in 173 -- Current_Exceptions (the DEC compatible unit). It is called from the 174 -- compiler generated code (using Rtsfind, which does not respect the 175 -- private barrier, so we can place this function in the private part 176 -- where the compiler can find it, but the spec is unchanged.) 177 178 procedure Raise_Exception_Always (E : Exception_Id; Message : String := ""); 179 pragma No_Return (Raise_Exception_Always); 180 pragma Export (Ada, Raise_Exception_Always, "__gnat_raise_exception"); 181 -- This differs from Raise_Exception only in that the caller has determined 182 -- that for sure the parameter E is not null, and that therefore no check 183 -- for Null_Id is required. The expander converts Raise_Exception calls to 184 -- Raise_Exception_Always if it can determine this is the case. The Export 185 -- allows this routine to be accessed from Pure units. 186 187 procedure Raise_From_Signal_Handler 188 (E : Exception_Id; 189 M : System.Address); 190 pragma Export 191 (Ada, Raise_From_Signal_Handler, 192 "ada__exceptions__raise_from_signal_handler"); 193 pragma No_Return (Raise_From_Signal_Handler); 194 -- This routine is used to raise an exception from a signal handler. The 195 -- signal handler has already stored the machine state (i.e. the state that 196 -- corresponds to the location at which the signal was raised). E is the 197 -- Exception_Id specifying what exception is being raised, and M is a 198 -- pointer to a null-terminated string which is the message to be raised. 199 -- Note that this routine never returns, so it is permissible to simply 200 -- jump to this routine, rather than call it. This may be appropriate for 201 -- systems where the right way to get out of signal handler is to alter the 202 -- PC value in the machine state or in some other way ask the operating 203 -- system to return here rather than to the original location. 204 205 procedure Raise_From_Controlled_Operation 206 (X : Ada.Exceptions.Exception_Occurrence); 207 pragma No_Return (Raise_From_Controlled_Operation); 208 pragma Export 209 (Ada, Raise_From_Controlled_Operation, 210 "__gnat_raise_from_controlled_operation"); 211 -- Raise Program_Error, providing information about X (an exception raised 212 -- during a controlled operation) in the exception message. 213 214 procedure Reraise_Library_Exception_If_Any; 215 pragma Export 216 (Ada, Reraise_Library_Exception_If_Any, 217 "__gnat_reraise_library_exception_if_any"); 218 -- If there was an exception raised during library-level finalization, 219 -- reraise the exception. 220 221 procedure Reraise_Occurrence_Always (X : Exception_Occurrence); 222 pragma No_Return (Reraise_Occurrence_Always); 223 -- This differs from Raise_Occurrence only in that the caller guarantees 224 -- that for sure the parameter X is not the null occurrence, and that 225 -- therefore this procedure cannot return. The expander uses this routine 226 -- in the translation of a raise statement with no parameter (reraise). 227 228 procedure Reraise_Occurrence_No_Defer (X : Exception_Occurrence); 229 pragma No_Return (Reraise_Occurrence_No_Defer); 230 -- Exactly like Reraise_Occurrence, except that abort is not deferred 231 -- before the call and the parameter X is known not to be the null 232 -- occurrence. This is used in generated code when it is known that abort 233 -- is already deferred. 234 235 function Triggered_By_Abort return Boolean; 236 -- Determine whether the current exception (if it exists) is an instance of 237 -- Standard'Abort_Signal. 238 239 -------------------------- 240 -- Exception_Occurrence -- 241 -------------------------- 242 243 package TBE renames System.Traceback_Entries; 244 245 Max_Tracebacks : constant := 50; 246 -- Maximum number of trace backs stored in exception occurrence 247 248 subtype Tracebacks_Array is TBE.Tracebacks_Array (1 .. Max_Tracebacks); 249 -- Traceback array stored in exception occurrence 250 251 type Exception_Occurrence is record 252 Id : Exception_Id := Null_Id; 253 -- Exception_Identity for this exception occurrence 254 255 Machine_Occurrence : System.Address; 256 -- The underlying machine occurrence. For GCC, this corresponds to the 257 -- _Unwind_Exception structure address. 258 259 Msg_Length : Natural := 0; 260 -- Length of message (zero = no message) 261 262 Msg : String (1 .. Exception_Msg_Max_Length); 263 -- Characters of message 264 265 Exception_Raised : Boolean := False; 266 -- Set to true to indicate that this exception occurrence has actually 267 -- been raised. When an exception occurrence is first created, this is 268 -- set to False, then when it is processed by Raise_Current_Exception, 269 -- it is set to True. If Raise_Current_Exception is used to raise an 270 -- exception for which this flag is already True, then it knows that 271 -- it is dealing with the reraise case (which is useful to distinguish 272 -- for exception tracing purposes). 273 274 Pid : Natural := 0; 275 -- Partition_Id for partition raising exception 276 277 Num_Tracebacks : Natural range 0 .. Max_Tracebacks := 0; 278 -- Number of traceback entries stored 279 280 Tracebacks : Tracebacks_Array; 281 -- Stored tracebacks (in Tracebacks (1 .. Num_Tracebacks)) 282 end record; 283 284 function "=" (Left, Right : Exception_Occurrence) return Boolean 285 is abstract; 286 -- Don't allow comparison on exception occurrences, we should not need 287 -- this, and it would not work right, because of the Msg and Tracebacks 288 -- fields which have unused entries not copied by Save_Occurrence. 289 290 function Get_Exception_Machine_Occurrence 291 (X : Exception_Occurrence) return System.Address; 292 pragma Export (Ada, Get_Exception_Machine_Occurrence, 293 "__gnat_get_exception_machine_occurrence"); 294 -- Get the machine occurrence corresponding to an exception occurrence. 295 -- It is Null_Address if there is no machine occurrence (in runtimes that 296 -- doesn't use GCC mechanism) or if it has been lost (Save_Occurrence 297 -- doesn't save the machine occurrence). 298 299 function EO_To_String (X : Exception_Occurrence) return String; 300 function String_To_EO (S : String) return Exception_Occurrence; 301 pragma Stream_Convert (Exception_Occurrence, String_To_EO, EO_To_String); 302 -- Functions for implementing Exception_Occurrence stream attributes 303 304 pragma Warnings (Off, "aggregate not fully initialized"); 305 Null_Occurrence : constant Exception_Occurrence := (others => <>); 306 pragma Warnings (On, "aggregate not fully initialized"); 307 308end Ada.Exceptions; 309