gcc/ada/libgnat/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) 2001-2017, 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 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 -- As a special exception under Section 7 of GPL version 3, you are granted --
  19 -- additional permissions described in the GCC Runtime Library Exception,   --
  20 -- version 3.1, as published by the Free Software Foundation.               --
  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 --  This version contains allocation tracking capability
  33
  34 --  The object file corresponding to this instrumented version is to be found
  35 --  in libgmem.
  36
  37 --  When enabled, the subsystem logs all the calls to __gnat_malloc and
  38 --  __gnat_free. This log can then be processed by gnatmem to detect
  39 --  dynamic memory leaks.
  40
  41 --  To use this functionality, you must compile your application with -g
  42 --  and then link with this object file:
  43
  44 --     gnatmake -g program -largs -lgmem
  45
  46 --  After compilation, you may use your program as usual except that upon
  47 --  completion, it will generate in the current directory the file gmem.out.
  48
  49 --  You can then investigate for possible memory leaks and mismatch by calling
  50 --  gnatmem with this file as an input:
  51
  52 --    gnatmem -i gmem.out program
  53
  54 --  See gnatmem section in the GNAT User's Guide for more details
  55
  56 --  NOTE: This capability is currently supported on the following targets:
  57
  58 --    Windows
  59 --    AIX
  60 --    GNU/Linux
  61 --    HP-UX
  62 --    Solaris
  63
  64 --  NOTE FOR FUTURE PLATFORMS SUPPORT: It is assumed that type Duration is
  65 --  64 bit. If the need arises to support architectures where this assumption
  66 --  is incorrect, it will require changing the way timestamps of allocation
  67 --  events are recorded.
  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 with System.Traceback_Entries;
  75 with GNAT.IO;
  76 with System.OS_Primitives;
  77
  78 package body System.Memory is
  79
  80    use Ada.Exceptions;
  81    use System.Soft_Links;
  82    use System.Traceback;
  83    use System.Traceback_Entries;
  84    use GNAT.IO;
  85
  86    function c_malloc (Size : size_t) return System.Address;
  87    pragma Import (C, c_malloc, "malloc");
  88
  89    procedure c_free (Ptr : System.Address);
  90    pragma Import (C, c_free, "free");
  91
  92    function c_realloc
  93      (Ptr : System.Address; Size : size_t) return System.Address;
  94    pragma Import (C, c_realloc, "realloc");
  95
  96    subtype File_Ptr is System.Address;
  97
  98    function fopen (Path : String; Mode : String) return File_Ptr;
  99    pragma Import (C, fopen);
 100
 101    procedure OS_Exit (Status : Integer);
 102    pragma Import (C, OS_Exit, "__gnat_os_exit");
 103    pragma No_Return (OS_Exit);
 104
 105    procedure fwrite
 106      (Ptr    : System.Address;
 107       Size   : size_t;
 108       Nmemb  : size_t;
 109       Stream : File_Ptr);
 110
 111    procedure fwrite
 112      (Str    : String;
 113       Size   : size_t;
 114       Nmemb  : size_t;
 115       Stream : File_Ptr);
 116    pragma Import (C, fwrite);
 117
 118    procedure fputc (C : Integer; Stream : File_Ptr);
 119    pragma Import (C, fputc);
 120
 121    procedure fclose (Stream : File_Ptr);
 122    pragma Import (C, fclose);
 123
 124    procedure Finalize;
 125    pragma Export (C, Finalize, "__gnat_finalize");
 126    --  Replace the default __gnat_finalize to properly close the log file
 127
 128    Address_Size : constant := System.Address'Max_Size_In_Storage_Elements;
 129    --  Size in bytes of a pointer
 130
 131    Max_Call_Stack : constant := 200;
 132    --  Maximum number of frames supported
 133
 134    Tracebk   : Tracebacks_Array (1 .. Max_Call_Stack);
 135    Num_Calls : aliased Integer := 0;
 136
 137    Gmemfname : constant String := "gmem.out" & ASCII.NUL;
 138    --  Allocation log of a program is saved in a file gmem.out
 139    --  ??? What about Ada.Command_Line.Command_Name & ".out" instead of static
 140    --  gmem.out
 141
 142    Gmemfile : File_Ptr;
 143    --  Global C file pointer to the allocation log
 144
 145    Needs_Init : Boolean := True;
 146    --  Reset after first call to Gmem_Initialize
 147
 148    procedure Gmem_Initialize;
 149    --  Initialization routine; opens the file and writes a header string. This
 150    --  header string is used as a magic-tag to know if the .out file is to be
 151    --  handled by GDB or by the GMEM (instrumented malloc/free) implementation.
 152
 153    First_Call : Boolean := True;
 154    --  Depending on implementation, some of the traceback routines may
 155    --  themselves do dynamic allocation. We use First_Call flag to avoid
 156    --  infinite recursion
 157
 158    -----------
 159    -- Alloc --
 160    -----------
 161
 162    function Alloc (Size : size_t) return System.Address is
 163       Result      : aliased System.Address;
 164       Actual_Size : aliased size_t := Size;
 165       Timestamp   : aliased Duration;
 166
 167    begin
 168       if Size = size_t'Last then
 169          Raise_Exception (Storage_Error'Identity, "object too large");
 170       end if;
 171
 172       --  Change size from zero to non-zero. We still want a proper pointer
 173       --  for the zero case because pointers to zero length objects have to
 174       --  be distinct, but we can't just go ahead and allocate zero bytes,
 175       --  since some malloc's return zero for a zero argument.
 176
 177       if Size = 0 then
 178          Actual_Size := 1;
 179       end if;
 180
 181       Lock_Task.all;
 182
 183       Result := c_malloc (Actual_Size);
 184
 185       if First_Call then
 186
 187          --  Logs allocation call
 188          --  format is:
 189          --   'A' <mem addr> <size chunk> <len backtrace> <addr1> ... <addrn>
 190
 191          First_Call := False;
 192
 193          if Needs_Init then
 194             Gmem_Initialize;
 195          end if;
 196
 197          Timestamp := System.OS_Primitives.Clock;
 198          Call_Chain
 199            (Tracebk, Max_Call_Stack, Num_Calls, Skip_Frames => 2);
 200          fputc (Character'Pos ('A'), Gmemfile);
 201          fwrite (Result'Address, Address_Size, 1, Gmemfile);
 202          fwrite (Actual_Size'Address, size_t'Max_Size_In_Storage_Elements, 1,
 203                  Gmemfile);
 204          fwrite (Timestamp'Address, Duration'Max_Size_In_Storage_Elements, 1,
 205                  Gmemfile);
 206          fwrite (Num_Calls'Address, Integer'Max_Size_In_Storage_Elements, 1,
 207                  Gmemfile);
 208
 209          for J in Tracebk'First .. Tracebk'First + Num_Calls - 1 loop
 210             declare
 211                Ptr : System.Address := PC_For (Tracebk (J));
 212             begin
 213                fwrite (Ptr'Address, Address_Size, 1, Gmemfile);
 214             end;
 215          end loop;
 216
 217          First_Call := True;
 218
 219       end if;
 220
 221       Unlock_Task.all;
 222
 223       if Result = System.Null_Address then
 224          Raise_Exception (Storage_Error'Identity, "heap exhausted");
 225       end if;
 226
 227       return Result;
 228    end Alloc;
 229
 230    --------------
 231    -- Finalize --
 232    --------------
 233
 234    procedure Finalize is
 235    begin
 236       if not Needs_Init then
 237          fclose (Gmemfile);
 238       end if;
 239    end Finalize;
 240
 241    ----------
 242    -- Free --
 243    ----------
 244
 245    procedure Free (Ptr : System.Address) is
 246       Addr      : aliased constant System.Address := Ptr;
 247       Timestamp : aliased Duration;
 248
 249    begin
 250       Lock_Task.all;
 251
 252       if First_Call then
 253
 254          --  Logs deallocation call
 255          --  format is:
 256          --   'D' <mem addr> <len backtrace> <addr1> ... <addrn>
 257
 258          First_Call := False;
 259
 260          if Needs_Init then
 261             Gmem_Initialize;
 262          end if;
 263
 264          Call_Chain
 265            (Tracebk, Max_Call_Stack, Num_Calls, Skip_Frames => 2);
 266          Timestamp := System.OS_Primitives.Clock;
 267          fputc (Character'Pos ('D'), Gmemfile);
 268          fwrite (Addr'Address, Address_Size, 1, Gmemfile);
 269          fwrite (Timestamp'Address, Duration'Max_Size_In_Storage_Elements, 1,
 270                  Gmemfile);
 271          fwrite (Num_Calls'Address, Integer'Max_Size_In_Storage_Elements, 1,
 272                  Gmemfile);
 273
 274          for J in Tracebk'First .. Tracebk'First + Num_Calls - 1 loop
 275             declare
 276                Ptr : System.Address := PC_For (Tracebk (J));
 277             begin
 278                fwrite (Ptr'Address, Address_Size, 1, Gmemfile);
 279             end;
 280          end loop;
 281
 282          c_free (Ptr);
 283
 284          First_Call := True;
 285       end if;
 286
 287       Unlock_Task.all;
 288    end Free;
 289
 290    ---------------------
 291    -- Gmem_Initialize --
 292    ---------------------
 293
 294    procedure Gmem_Initialize is
 295       Timestamp : aliased Duration;
 296
 297    begin
 298       if Needs_Init then
 299          Needs_Init := False;
 300          System.OS_Primitives.Initialize;
 301          Timestamp := System.OS_Primitives.Clock;
 302          Gmemfile := fopen (Gmemfname, "wb" & ASCII.NUL);
 303
 304          if Gmemfile = System.Null_Address then
 305             Put_Line ("Couldn't open gnatmem log file for writing");
 306             OS_Exit (255);
 307          end if;
 308
 309          fwrite ("GMEM DUMP" & ASCII.LF, 10, 1, Gmemfile);
 310          fwrite (Timestamp'Address, Duration'Max_Size_In_Storage_Elements, 1,
 311                  Gmemfile);
 312       end if;
 313    end Gmem_Initialize;
 314
 315    -------------
 316    -- Realloc --
 317    -------------
 318
 319    function Realloc
 320      (Ptr  : System.Address;
 321       Size : size_t) return System.Address
 322    is
 323       Addr      : aliased constant System.Address := Ptr;
 324       Result    : aliased System.Address;
 325       Timestamp : aliased Duration;
 326
 327    begin
 328       --  For the purposes of allocations logging, we treat realloc as a free
 329       --  followed by malloc. This is not exactly accurate, but is a good way
 330       --  to fit it into malloc/free-centered reports.
 331
 332       if Size = size_t'Last then
 333          Raise_Exception (Storage_Error'Identity, "object too large");
 334       end if;
 335
 336       Abort_Defer.all;
 337       Lock_Task.all;
 338
 339       if First_Call then
 340          First_Call := False;
 341
 342          --  We first log deallocation call
 343
 344          if Needs_Init then
 345             Gmem_Initialize;
 346          end if;
 347          Call_Chain
 348            (Tracebk, Max_Call_Stack, Num_Calls, Skip_Frames => 2);
 349          Timestamp := System.OS_Primitives.Clock;
 350          fputc (Character'Pos ('D'), Gmemfile);
 351          fwrite (Addr'Address, Address_Size, 1, Gmemfile);
 352          fwrite (Timestamp'Address, Duration'Max_Size_In_Storage_Elements, 1,
 353                  Gmemfile);
 354          fwrite (Num_Calls'Address, Integer'Max_Size_In_Storage_Elements, 1,
 355                  Gmemfile);
 356
 357          for J in Tracebk'First .. Tracebk'First + Num_Calls - 1 loop
 358             declare
 359                Ptr : System.Address := PC_For (Tracebk (J));
 360             begin
 361                fwrite (Ptr'Address, Address_Size, 1, Gmemfile);
 362             end;
 363          end loop;
 364
 365          --  Now perform actual realloc
 366
 367          Result := c_realloc (Ptr, Size);
 368
 369          --   Log allocation call using the same backtrace
 370
 371          fputc (Character'Pos ('A'), Gmemfile);
 372          fwrite (Result'Address, Address_Size, 1, Gmemfile);
 373          fwrite (Size'Address, size_t'Max_Size_In_Storage_Elements, 1,
 374                  Gmemfile);
 375          fwrite (Timestamp'Address, Duration'Max_Size_In_Storage_Elements, 1,
 376                  Gmemfile);
 377          fwrite (Num_Calls'Address, Integer'Max_Size_In_Storage_Elements, 1,
 378                  Gmemfile);
 379
 380          for J in Tracebk'First .. Tracebk'First + Num_Calls - 1 loop
 381             declare
 382                Ptr : System.Address := PC_For (Tracebk (J));
 383             begin
 384                fwrite (Ptr'Address, Address_Size, 1, Gmemfile);
 385             end;
 386          end loop;
 387
 388          First_Call := True;
 389       end if;
 390
 391       Unlock_Task.all;
 392       Abort_Undefer.all;
 393
 394       if Result = System.Null_Address then
 395          Raise_Exception (Storage_Error'Identity, "heap exhausted");
 396       end if;
 397
 398       return Result;
 399    end Realloc;
 400
 401 end System.Memory;