aboutsummaryrefslogtreecommitdiff
path: root/gcc/ada/s-memory.adb
blob: 66637c7291b6a2a07d8a10207149e15299d95d50 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
------------------------------------------------------------------------------
--                                                                          --
--                         GNAT RUN-TIME COMPONENTS                         --
--                                                                          --
--                         S Y S T E M . M E M O R Y                        --
--                                                                          --
--                                 B o d y                                  --
--                                                                          --
--          Copyright (C) 2001-2003 Free Software Foundation, Inc.          --
--                                                                          --
-- GNAT is free software;  you can  redistribute it  and/or modify it under --
-- terms of the  GNU General Public License as published  by the Free Soft- --
-- ware  Foundation;  either version 2,  or (at your option) any later ver- --
-- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --
-- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
-- or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License --
-- for  more details.  You should have  received  a copy of the GNU General --
-- Public License  distributed with GNAT;  see file COPYING.  If not, write --
-- to  the Free Software Foundation,  59 Temple Place - Suite 330,  Boston, --
-- MA 02111-1307, USA.                                                      --
--                                                                          --
-- As a special exception,  if other files  instantiate  generics from this --
-- unit, or you link  this unit with other files  to produce an executable, --
-- this  unit  does not  by itself cause  the resulting  executable  to  be --
-- covered  by the  GNU  General  Public  License.  This exception does not --
-- however invalidate  any other reasons why  the executable file  might be --
-- covered by the  GNU Public License.                                      --
--                                                                          --
-- GNAT was originally developed  by the GNAT team at  New York University. --
-- Extensive contributions were provided by Ada Core Technologies Inc.      --
--                                                                          --
------------------------------------------------------------------------------

--  This is the default implementation of this package.

--  This implementation assumes that the underlying malloc/free/realloc
--  implementation is thread safe, and thus, no additional lock is required.
--  Note that we still need to defer abortion because on most systems,
--  an asynchronous signal (as used for implementing asynchronous abortion
--  of task) cannot safely be handled while malloc is executing.

--  If you are not using Ada constructs containing the "abort" keyword,
--  then you can remove the calls to Abort_Defer.all and Abort_Undefer.all
--  from this unit.

with Ada.Exceptions;
with System.Soft_Links;
with System.Parameters;
with System.CRTL;

package body System.Memory is

   use Ada.Exceptions;
   use System.Soft_Links;

   function c_malloc (Size : System.CRTL.size_t) return System.Address
    renames System.CRTL.malloc;

   procedure c_free (Ptr : System.Address)
     renames System.CRTL.free;

   function c_realloc
     (Ptr : System.Address; Size : System.CRTL.size_t) return System.Address
     renames System.CRTL.realloc;

   -----------
   -- Alloc --
   -----------

   function Alloc (Size : size_t) return System.Address is
      Result      : System.Address;
      Actual_Size : size_t := Size;

   begin
      if Size = size_t'Last then
         Raise_Exception (Storage_Error'Identity, "object too large");
      end if;

      --  Change size from zero to non-zero. We still want a proper pointer
      --  for the zero case because pointers to zero length objects have to
      --  be distinct, but we can't just go ahead and allocate zero bytes,
      --  since some malloc's return zero for a zero argument.

      if Size = 0 then
         Actual_Size := 1;
      end if;

      if Parameters.No_Abort then
         Result := c_malloc (System.CRTL.size_t (Actual_Size));
      else
         Abort_Defer.all;
         Result := c_malloc (System.CRTL.size_t (Actual_Size));
         Abort_Undefer.all;
      end if;

      if Result = System.Null_Address then
         Raise_Exception (Storage_Error'Identity, "heap exhausted");
      end if;

      return Result;
   end Alloc;

   ----------
   -- Free --
   ----------

   procedure Free (Ptr : System.Address) is
   begin
      if Parameters.No_Abort then
         c_free (Ptr);
      else
         Abort_Defer.all;
         c_free (Ptr);
         Abort_Undefer.all;
      end if;
   end Free;

   -------------
   -- Realloc --
   -------------

   function Realloc
     (Ptr  : System.Address;
      Size : size_t)
      return System.Address
   is
      Result      : System.Address;
      Actual_Size : constant size_t := Size;

   begin
      if Size = size_t'Last then
         Raise_Exception (Storage_Error'Identity, "object too large");
      end if;

      if Parameters.No_Abort then
         Result := c_realloc (Ptr, System.CRTL.size_t (Actual_Size));
      else
         Abort_Defer.all;
         Result := c_realloc (Ptr, System.CRTL.size_t (Actual_Size));
         Abort_Undefer.all;
      end if;

      if Result = System.Null_Address then
         Raise_Exception (Storage_Error'Identity, "heap exhausted");
      end if;

      return Result;
   end Realloc;

end System.Memory;