File : s-exctra.adb
1 ------------------------------------------------------------------------------
2 -- --
3 -- GNAT RUN-TIME COMPONENTS --
4 -- --
5 -- S Y S T E M . E X C E P T I O N _ T R A C E S --
6 -- --
7 -- B o d y --
8 -- --
9 -- Copyright (C) 2000-2015, AdaCore --
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. --
17 -- --
18 -- --
19 -- --
20 -- --
21 -- --
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/>. --
26 -- --
27 -- GNAT was originally developed by the GNAT team at New York University. --
28 -- Extensive contributions were provided by Ada Core Technologies Inc. --
29 -- --
30 ------------------------------------------------------------------------------
31
32 with Ada.Unchecked_Conversion;
33
34 with System.Standard_Library; use System.Standard_Library;
35 with System.Soft_Links; use System.Soft_Links;
36
37 package body System.Exception_Traces is
38
39 -- Calling the decorator directly from where it is needed would require
40 -- introducing nasty dependencies upon the spec of this package (typically
41 -- in a-except.adb). We also have to deal with the fact that the traceback
42 -- array within an exception occurrence and the one the decorator accepts
43 -- are of different types. These are two reasons for which a wrapper with
44 -- a System.Address argument is indeed used to call the decorator provided
45 -- by the user of this package. This wrapper is called via a soft-link,
46 -- which either is null when no decorator is in place or "points to" the
47 -- following function otherwise.
48
49 function Decorator_Wrapper
50 (Traceback : System.Address;
51 Len : Natural) return String;
52 -- The wrapper to be called when a decorator is in place for exception
53 -- backtraces.
54 --
55 -- Traceback is the address of the call chain array as stored in the
56 -- exception occurrence and Len is the number of significant addresses
57 -- contained in this array.
58
59 Current_Decorator : Traceback_Decorator := null;
60 -- The decorator to be called by the wrapper when it is not null, as set
61 -- by Set_Trace_Decorator. When this access is null, the wrapper is null
62 -- also and shall then not be called.
63
64 -----------------------
65 -- Decorator_Wrapper --
66 -----------------------
67
68 function Decorator_Wrapper
69 (Traceback : System.Address;
70 Len : Natural) return String
71 is
72 subtype Trace_Array is Traceback_Entries.Tracebacks_Array (1 .. Len);
73 type Trace_Array_Access is access all Trace_Array;
74
75 function To_Trace_Array is new
76 Ada.Unchecked_Conversion (Address, Trace_Array_Access);
77
78 Decorator_Traceback : constant Trace_Array_Access :=
79 To_Trace_Array (Traceback);
80
81 begin
82 return Current_Decorator.all (Decorator_Traceback.all);
83 end Decorator_Wrapper;
84
85 -------------------------
86 -- Set_Trace_Decorator --
87 -------------------------
88
89 procedure Set_Trace_Decorator (Decorator : Traceback_Decorator) is
90 begin
91 Current_Decorator := Decorator;
92 Traceback_Decorator_Wrapper :=
93 (if Current_Decorator /= null
94 then Decorator_Wrapper'Access else null);
95 end Set_Trace_Decorator;
96
97 ---------------
98 -- Trace_Off --
99 ---------------
100
101 procedure Trace_Off is
102 begin
103 Exception_Trace := RM_Convention;
104 end Trace_Off;
105
106 --------------
107 -- Trace_On --
108 --------------
109
110 procedure Trace_On (Kind : Trace_Kind) is
111 begin
112 case Kind is
113 when Every_Raise =>
114 Exception_Trace := Every_Raise;
115 when Unhandled_Raise =>
116 Exception_Trace := Unhandled_Raise;
117 when Unhandled_Raise_In_Main =>
118 Exception_Trace := Unhandled_Raise_In_Main;
119 end case;
120 end Trace_On;
121
122 end System.Exception_Traces;