gcc/ada/memtrack.adb

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                         GNAT RUN-TIME COMPONENTS                         --
   4 --                                                                          --
   5 --                         S Y S T E M . M E M O R Y                        --
   6 --                                                                          --
   7 --                                 S p e c                                  --
   8 --                                                                          --
   9 --             Copyright (C) 2001 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 2,  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.  See the GNU General Public License --
  21 -- for  more details.  You should have  received  a copy of the GNU General --
  22 -- Public License  distributed with GNAT;  see file COPYING.  If not, write --
  23 -- to  the Free Software Foundation,  59 Temple Place - Suite 330,  Boston, --
  24 -- MA 02111-1307, USA.                                                      --
  25 --                                                                          --
  26 -- As a special exception,  if other files  instantiate  generics from this --
  27 -- unit, or you link  this unit with other files  to produce an executable, --
  28 -- this  unit  does not  by itself cause  the resulting  executable  to  be --
  29 -- covered  by the  GNU  General  Public  License.  This exception does not --
  30 -- however invalidate  any other reasons why  the executable file  might be --
  31 -- covered by the  GNU Public License.                                      --
  32 --                                                                          --
  33 -- GNAT was originally developed  by the GNAT team at  New York University. --
  34 -- Extensive contributions were provided by Ada Core Technologies Inc.      --
  35 --                                                                          --
  36 ------------------------------------------------------------------------------
  37
  38 --  This version contains allocation tracking capability.
  39 --  The object file corresponding to this instrumented version is to be found
  40 --  in libgmem.
  41 --  When enabled, the subsystem logs all the calls to __gnat_malloc and
  42 --  __gnat_free. This log can then be processed by gnatmem to detect
  43 --  dynamic memory leaks.
  44 --
  45 --  To use this functionality, you must compile your application with -g
  46 --  and then link with this object file:
  47 --
  48 --     gnatmake -g program -largs -lgmem
  49 --
  50 --  After compilation, you may use your program as usual except that upon
  51 --  completion, it will generate in the current directory the file gmem.out.
  52 --
  53 --  You can then investigate for possible memory leaks and mismatch by calling
  54 --  gnatmem with this file as an input:
  55 --
  56 --    gnatmem -i gmem.out program
  57 --
  58 --  See gnatmem section in the GNAT User's Guide for more details.
  59 --
  60 --  NOTE: This capability is currently supported on the following targets:
  61 --
  62 --    Windows
  63 --    GNU/Linux
  64 --    HP-UX
  65 --    Irix
  66 --    Solaris
  67 --    Tru64
  68
  69 pragma Source_File_Name (System.Memory, Body_File_Name => "memtrack.adb");
  70
  71 with Ada.Exceptions;
  72 with System.Soft_Links;
  73 with System.Traceback;
  74
  75 package body System.Memory is
  76
  77    use Ada.Exceptions;
  78    use System.Soft_Links;
  79    use System.Traceback;
  80
  81    function c_malloc (Size : size_t) return System.Address;
  82    pragma Import (C, c_malloc, "malloc");
  83
  84    procedure c_free (Ptr : System.Address);
  85    pragma Import (C, c_free, "free");
  86
  87    function c_realloc
  88      (Ptr : System.Address; Size : size_t) return System.Address;
  89    pragma Import (C, c_realloc, "realloc");
  90
  91    type File_Ptr is new System.Address;
  92
  93    function fopen (Path : String; Mode : String) return File_Ptr;
  94    pragma Import (C, fopen);
  95
  96    procedure fwrite
  97      (Ptr    : System.Address;
  98       Size   : size_t;
  99       Nmemb  : size_t;
 100       Stream : File_Ptr);
 101
 102    procedure fwrite
 103      (Str    : String;
 104       Size   : size_t;
 105       Nmemb  : size_t;
 106       Stream : File_Ptr);
 107    pragma Import (C, fwrite);
 108
 109    procedure fputc (C : Integer; Stream : File_Ptr);
 110    pragma Import (C, fputc);
 111
 112    procedure fclose (Stream : File_Ptr);
 113    pragma Import (C, fclose);
 114
 115    procedure Finalize;
 116    --  Replace the default __gnat_finalize to properly close the log file.
 117    pragma Export (C, Finalize, "__gnat_finalize");
 118
 119    Address_Size    : constant := System.Address'Max_Size_In_Storage_Elements;
 120    --  Size in bytes of a pointer
 121
 122    Max_Call_Stack  : constant := 200;
 123    --  Maximum number of frames supported
 124
 125    Skip_Frame : constant := 1;
 126    --  Number of frames to remove from the call stack to hide functions from
 127    --  this unit.
 128
 129    Tracebk   : aliased array (0 .. Max_Call_Stack) of System.Address;
 130    Num_Calls : aliased Integer := 0;
 131    --  Store the current call stack from Alloc and Free
 132
 133    Gmemfname : constant String := "gmem.out" & ASCII.NUL;
 134    --  Allocation log of a program is saved in a file gmem.out
 135    --  ??? What about Ada.Command_Line.Command_Name & ".out" instead of static
 136    --  gmem.out
 137
 138    Gmemfile  : File_Ptr;
 139    --  Global C file pointer to the allocation log
 140
 141    procedure Gmem_Initialize;
 142    --  Initialization routine; opens the file and writes a header string. This
 143    --  header string is used as a magic-tag to know if the .out file is to be
 144    --  handled by GDB or by the GMEM (instrumented malloc/free) implementation.
 145
 146    -----------
 147    -- Alloc --
 148    -----------
 149
 150    function Alloc (Size : size_t) return System.Address is
 151       Result      : aliased System.Address;
 152       Actual_Size : aliased size_t := Size;
 153
 154    begin
 155       if Size = size_t'Last then
 156          Raise_Exception (Storage_Error'Identity, "object too large");
 157       end if;
 158
 159       --  Change size from zero to non-zero. We still want a proper pointer
 160       --  for the zero case because pointers to zero length objects have to
 161       --  be distinct, but we can't just go ahead and allocate zero bytes,
 162       --  since some malloc's return zero for a zero argument.
 163
 164       if Size = 0 then
 165          Actual_Size := 1;
 166       end if;
 167
 168       Lock_Task.all;
 169
 170       Result := c_malloc (Actual_Size);
 171
 172       --  Logs allocation call
 173       --  format is:
 174       --   'A' <mem addr> <size chunk> <len backtrace> <addr1> ... <addrn>
 175
 176       Gmem_Initialize;
 177       Call_Chain (Tracebk'Address, Max_Call_Stack, Num_Calls);
 178       Num_Calls := Num_Calls - Skip_Frame;
 179       fputc (Character'Pos ('A'), Gmemfile);
 180       fwrite (Result'Address, Address_Size, 1, Gmemfile);
 181       fwrite (Actual_Size'Address, size_t'Max_Size_In_Storage_Elements, 1,
 182               Gmemfile);
 183       fwrite (Num_Calls'Address, Integer'Max_Size_In_Storage_Elements, 1,
 184               Gmemfile);
 185       fwrite (Tracebk (Skip_Frame)'Address, Address_Size, size_t (Num_Calls),
 186               Gmemfile);
 187
 188       Unlock_Task.all;
 189
 190       if Result = System.Null_Address then
 191          Raise_Exception (Storage_Error'Identity, "heap exhausted");
 192       end if;
 193
 194       return Result;
 195    end Alloc;
 196
 197    --------------
 198    -- Finalize --
 199    --------------
 200
 201    Needs_Init : Boolean := True;
 202    --  Reset after first call to Gmem_Initialize
 203
 204    procedure Finalize is
 205    begin
 206       if not Needs_Init then
 207          fclose (Gmemfile);
 208       end if;
 209    end Finalize;
 210
 211    ----------
 212    -- Free --
 213    ----------
 214
 215    procedure Free (Ptr : System.Address) is
 216       Addr : aliased constant System.Address := Ptr;
 217    begin
 218       Lock_Task.all;
 219
 220       --  Logs deallocation call
 221       --  format is:
 222       --   'D' <mem addr> <len backtrace> <addr1> ... <addrn>
 223
 224       Gmem_Initialize;
 225       Call_Chain (Tracebk'Address, Max_Call_Stack, Num_Calls);
 226       Num_Calls := Num_Calls - Skip_Frame;
 227       fputc (Character'Pos ('D'), Gmemfile);
 228       fwrite (Addr'Address, Address_Size, 1, Gmemfile);
 229       fwrite (Num_Calls'Address, Integer'Max_Size_In_Storage_Elements, 1,
 230               Gmemfile);
 231       fwrite (Tracebk (Skip_Frame)'Address, Address_Size, size_t (Num_Calls),
 232               Gmemfile);
 233
 234       c_free (Ptr);
 235
 236       Unlock_Task.all;
 237    end Free;
 238
 239    ---------------------
 240    -- Gmem_Initialize --
 241    ---------------------
 242
 243    procedure Gmem_Initialize is
 244    begin
 245       if Needs_Init then
 246          Needs_Init := False;
 247          Gmemfile := fopen (Gmemfname, "wb" & ASCII.NUL);
 248          fwrite ("GMEM DUMP" & ASCII.LF, 10, 1, Gmemfile);
 249       end if;
 250    end Gmem_Initialize;
 251
 252    -------------
 253    -- Realloc --
 254    -------------
 255
 256    function Realloc
 257      (Ptr : System.Address; Size : size_t) return System.Address
 258    is
 259       Result : System.Address;
 260    begin
 261       if Size = size_t'Last then
 262          Raise_Exception (Storage_Error'Identity, "object too large");
 263       end if;
 264
 265       Abort_Defer.all;
 266       Result := c_realloc (Ptr, Size);
 267       Abort_Undefer.all;
 268
 269       if Result = System.Null_Address then
 270          Raise_Exception (Storage_Error'Identity, "heap exhausted");
 271       end if;
 272
 273       return Result;
 274    end Realloc;
 275
 276 end System.Memory;