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 --                                 B o d y                                  --
   8 --                                                                          --
   9 --          Copyright (C) 2001-2005 Free Software Foundation, Inc.          --
  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 2,  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.  See the GNU General Public License --
  17 -- for  more details.  You should have  received  a copy of the GNU General --
  18 -- Public License  distributed with GNAT;  see file COPYING.  If not, write --
  19 -- to  the  Free Software Foundation,  51  Franklin  Street,  Fifth  Floor, --
  20 -- Boston, MA 02110-1301, USA.                                              --
  21 --                                                                          --
  22 -- As a special exception,  if other files  instantiate  generics from this --
  23 -- unit, or you link  this unit with other files  to produce an executable, --
  24 -- this  unit  does not  by itself cause  the resulting  executable  to  be --
  25 -- covered  by the  GNU  General  Public  License.  This exception does not --
  26 -- however invalidate  any other reasons why  the executable file  might be --
  27 -- covered by the  GNU Public License.                                      --
  28 --                                                                          --
  29 -- GNAT was originally developed  by the GNAT team at  New York University. --
  30 -- Extensive contributions were provided by Ada Core Technologies Inc.      --
  31 --                                                                          --
  32 ------------------------------------------------------------------------------
  33
  34 --  This version contains allocation tracking capability
  35
  36 --  The object file corresponding to this instrumented version is to be found
  37 --  in libgmem.
  38
  39 --  When enabled, the subsystem logs all the calls to __gnat_malloc and
  40 --  __gnat_free. This log can then be processed by gnatmem to detect
  41 --  dynamic memory leaks.
  42
  43 --  To use this functionality, you must compile your application with -g
  44 --  and then link with this object file:
  45
  46 --     gnatmake -g program -largs -lgmem
  47
  48 --  After compilation, you may use your program as usual except that upon
  49 --  completion, it will generate in the current directory the file gmem.out.
  50
  51 --  You can then investigate for possible memory leaks and mismatch by calling
  52 --  gnatmem with this file as an input:
  53
  54 --    gnatmem -i gmem.out program
  55
  56 --  See gnatmem section in the GNAT User's Guide for more details
  57
  58 --  NOTE: This capability is currently supported on the following targets:
  59
  60 --    Windows
  61 --    AIX
  62 --    GNU/Linux
  63 --    HP-UX
  64 --    Irix
  65 --    Solaris
  66 --    Tru64
  67
  68 pragma Source_File_Name (System.Memory, Body_File_Name => "memtrack.adb");
  69
  70 with Ada.Exceptions;
  71 with System.Soft_Links;
  72 with System.Traceback;
  73 with System.Traceback_Entries;
  74 with GNAT.IO;
  75
  76 package body System.Memory is
  77
  78    use Ada.Exceptions;
  79    use System.Soft_Links;
  80    use System.Traceback;
  81    use System.Traceback_Entries;
  82    use GNAT.IO;
  83
  84    function c_malloc (Size : size_t) return System.Address;
  85    pragma Import (C, c_malloc, "malloc");
  86
  87    procedure c_free (Ptr : System.Address);
  88    pragma Import (C, c_free, "free");
  89
  90    function c_realloc
  91      (Ptr : System.Address; Size : size_t) return System.Address;
  92    pragma Import (C, c_realloc, "realloc");
  93
  94    subtype File_Ptr is System.Address;
  95
  96    function fopen (Path : String; Mode : String) return File_Ptr;
  97    pragma Import (C, fopen);
  98
  99    procedure OS_Exit (Status : Integer);
 100    pragma Import (C, OS_Exit, "__gnat_os_exit");
 101    pragma No_Return (OS_Exit);
 102
 103    procedure fwrite
 104      (Ptr    : System.Address;
 105       Size   : size_t;
 106       Nmemb  : size_t;
 107       Stream : File_Ptr);
 108
 109    procedure fwrite
 110      (Str    : String;
 111       Size   : size_t;
 112       Nmemb  : size_t;
 113       Stream : File_Ptr);
 114    pragma Import (C, fwrite);
 115
 116    procedure fputc (C : Integer; Stream : File_Ptr);
 117    pragma Import (C, fputc);
 118
 119    procedure fclose (Stream : File_Ptr);
 120    pragma Import (C, fclose);
 121
 122    procedure Finalize;
 123    pragma Export (C, Finalize, "__gnat_finalize");
 124    --  Replace the default __gnat_finalize to properly close the log file
 125
 126    Address_Size : constant := System.Address'Max_Size_In_Storage_Elements;
 127    --  Size in bytes of a pointer
 128
 129    Max_Call_Stack : constant := 200;
 130    --  Maximum number of frames supported
 131
 132    Tracebk   : aliased array (0 .. Max_Call_Stack) of Traceback_Entry;
 133    Num_Calls : aliased Integer := 0;
 134
 135    Gmemfname : constant String := "gmem.out" & ASCII.NUL;
 136    --  Allocation log of a program is saved in a file gmem.out
 137    --  ??? What about Ada.Command_Line.Command_Name & ".out" instead of static
 138    --  gmem.out
 139
 140    Gmemfile : File_Ptr;
 141    --  Global C file pointer to the allocation log
 142
 143    procedure Gmem_Initialize;
 144    --  Initialization routine; opens the file and writes a header string. This
 145    --  header string is used as a magic-tag to know if the .out file is to be
 146    --  handled by GDB or by the GMEM (instrumented malloc/free) implementation.
 147
 148    First_Call : Boolean := True;
 149    --  Depending on implementation, some of the traceback routines may
 150    --  themselves do dynamic allocation. We use First_Call flag to avoid
 151    --  infinite recursion
 152
 153    -----------
 154    -- Alloc --
 155    -----------
 156
 157    function Alloc (Size : size_t) return System.Address is
 158       Result      : aliased System.Address;
 159       Actual_Size : aliased size_t := Size;
 160
 161    begin
 162       if Size = size_t'Last then
 163          Raise_Exception (Storage_Error'Identity, "object too large");
 164       end if;
 165
 166       --  Change size from zero to non-zero. We still want a proper pointer
 167       --  for the zero case because pointers to zero length objects have to
 168       --  be distinct, but we can't just go ahead and allocate zero bytes,
 169       --  since some malloc's return zero for a zero argument.
 170
 171       if Size = 0 then
 172          Actual_Size := 1;
 173       end if;
 174
 175       Lock_Task.all;
 176
 177       Result := c_malloc (Actual_Size);
 178
 179       if First_Call then
 180
 181          --  Logs allocation call
 182          --  format is:
 183          --   'A' <mem addr> <size chunk> <len backtrace> <addr1> ... <addrn>
 184
 185          First_Call := False;
 186
 187          Gmem_Initialize;
 188          Call_Chain (Tracebk'Address, Max_Call_Stack, Num_Calls,
 189                      Skip_Frames => 2);
 190          fputc (Character'Pos ('A'), Gmemfile);
 191          fwrite (Result'Address, Address_Size, 1, Gmemfile);
 192          fwrite (Actual_Size'Address, size_t'Max_Size_In_Storage_Elements, 1,
 193                  Gmemfile);
 194          fwrite (Num_Calls'Address, Integer'Max_Size_In_Storage_Elements, 1,
 195                  Gmemfile);
 196
 197          for J in Tracebk'First .. Tracebk'First + Num_Calls - 1 loop
 198             declare
 199                Ptr : System.Address := PC_For (Tracebk (J));
 200             begin
 201                fwrite (Ptr'Address, Address_Size, 1, Gmemfile);
 202             end;
 203          end loop;
 204
 205          First_Call := True;
 206
 207       end if;
 208
 209       Unlock_Task.all;
 210
 211       if Result = System.Null_Address then
 212          Raise_Exception (Storage_Error'Identity, "heap exhausted");
 213       end if;
 214
 215       return Result;
 216    end Alloc;
 217
 218    --------------
 219    -- Finalize --
 220    --------------
 221
 222    Needs_Init : Boolean := True;
 223    --  Reset after first call to Gmem_Initialize
 224
 225    procedure Finalize is
 226    begin
 227       if not Needs_Init then
 228          fclose (Gmemfile);
 229       end if;
 230    end Finalize;
 231
 232    ----------
 233    -- Free --
 234    ----------
 235
 236    procedure Free (Ptr : System.Address) is
 237       Addr : aliased constant System.Address := Ptr;
 238
 239    begin
 240       Lock_Task.all;
 241
 242       if First_Call then
 243
 244          --  Logs deallocation call
 245          --  format is:
 246          --   'D' <mem addr> <len backtrace> <addr1> ... <addrn>
 247
 248          First_Call := False;
 249
 250          Gmem_Initialize;
 251          Call_Chain (Tracebk'Address, Max_Call_Stack, Num_Calls,
 252                      Skip_Frames => 2);
 253          fputc (Character'Pos ('D'), Gmemfile);
 254          fwrite (Addr'Address, Address_Size, 1, Gmemfile);
 255          fwrite (Num_Calls'Address, Integer'Max_Size_In_Storage_Elements, 1,
 256                  Gmemfile);
 257
 258          for J in Tracebk'First .. Tracebk'First + Num_Calls - 1 loop
 259             declare
 260                Ptr : System.Address := PC_For (Tracebk (J));
 261             begin
 262                fwrite (Ptr'Address, Address_Size, 1, Gmemfile);
 263             end;
 264          end loop;
 265
 266          c_free (Ptr);
 267
 268          First_Call := True;
 269       end if;
 270
 271       Unlock_Task.all;
 272    end Free;
 273
 274    ---------------------
 275    -- Gmem_Initialize --
 276    ---------------------
 277
 278    procedure Gmem_Initialize is
 279    begin
 280       if Needs_Init then
 281          Needs_Init := False;
 282          Gmemfile := fopen (Gmemfname, "wb" & ASCII.NUL);
 283
 284          if Gmemfile = System.Null_Address then
 285             Put_Line ("Couldn't open gnatmem log file for writing");
 286             OS_Exit (255);
 287          end if;
 288
 289          fwrite ("GMEM DUMP" & ASCII.LF, 10, 1, Gmemfile);
 290       end if;
 291    end Gmem_Initialize;
 292
 293    -------------
 294    -- Realloc --
 295    -------------
 296
 297    function Realloc
 298      (Ptr : System.Address; Size : size_t) return System.Address
 299    is
 300       Addr : aliased constant System.Address := Ptr;
 301       Result : aliased System.Address;
 302
 303    begin
 304       --  For the purposes of allocations logging, we treat realloc as a free
 305       --  followed by malloc. This is not exactly accurate, but is a good way
 306       --  to fit it into malloc/free-centered reports.
 307
 308       if Size = size_t'Last then
 309          Raise_Exception (Storage_Error'Identity, "object too large");
 310       end if;
 311
 312       Abort_Defer.all;
 313       Lock_Task.all;
 314
 315       if First_Call then
 316          First_Call := False;
 317
 318          --  We first log deallocation call
 319
 320          Gmem_Initialize;
 321          Call_Chain (Tracebk'Address, Max_Call_Stack, Num_Calls,
 322                      Skip_Frames => 2);
 323          fputc (Character'Pos ('D'), Gmemfile);
 324          fwrite (Addr'Address, Address_Size, 1, Gmemfile);
 325          fwrite (Num_Calls'Address, Integer'Max_Size_In_Storage_Elements, 1,
 326                  Gmemfile);
 327
 328          for J in Tracebk'First .. Tracebk'First + Num_Calls - 1 loop
 329             declare
 330                Ptr : System.Address := PC_For (Tracebk (J));
 331             begin
 332                fwrite (Ptr'Address, Address_Size, 1, Gmemfile);
 333             end;
 334          end loop;
 335
 336          --  Now perform actual realloc
 337
 338          Result := c_realloc (Ptr, Size);
 339
 340          --   Log allocation call using the same backtrace
 341
 342          fputc (Character'Pos ('A'), Gmemfile);
 343          fwrite (Result'Address, Address_Size, 1, Gmemfile);
 344          fwrite (Size'Address, size_t'Max_Size_In_Storage_Elements, 1,
 345                  Gmemfile);
 346          fwrite (Num_Calls'Address, Integer'Max_Size_In_Storage_Elements, 1,
 347                  Gmemfile);
 348
 349          for J in Tracebk'First .. Tracebk'First + Num_Calls - 1 loop
 350             declare
 351                Ptr : System.Address := PC_For (Tracebk (J));
 352             begin
 353                fwrite (Ptr'Address, Address_Size, 1, Gmemfile);
 354             end;
 355          end loop;
 356
 357          First_Call := True;
 358       end if;
 359
 360       Unlock_Task.all;
 361       Abort_Undefer.all;
 362
 363       if Result = System.Null_Address then
 364          Raise_Exception (Storage_Error'Identity, "heap exhausted");
 365       end if;
 366
 367       return Result;
 368    end Realloc;
 369
 370 end System.Memory;