gcc/ada/vxaddr2line.adb

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                         GNAT COMPILER COMPONENTS                         --
   4 --                                                                          --
   5 --                           V X A D D R 2 L I N E                          --
   6 --                                                                          --
   7 --                                 B o d y                                  --
   8 --                                                                          --
   9 --                     Copyright (C) 2002-2009, 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.  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 COPYING3.  If not, go to --
  19 -- http://www.gnu.org/licenses for a complete copy of the license.          --
  20 --                                                                          --
  21 -- GNAT was originally developed  by the GNAT team at  New York University. --
  22 -- Extensive contributions were provided by Ada Core Technologies Inc.      --
  23 --                                                                          --
  24 ------------------------------------------------------------------------------
  25
  26 --  This program is meant to be used with vxworks to compute symbolic
  27 --  backtraces on the host from non-symbolic backtraces obtained on the target.
  28
  29 --  The basic idea is to automate the computation of the necessary address
  30 --  adjustments prior to calling addr2line when the application has only been
  31 --  partially linked on the host.
  32
  33 --  Variants for various targets are supported, and the command line should
  34 --  be like :
  35
  36 --  <target>-addr2line [-a <target_arch>] <exe_file> <ref_address>
  37 --                     <backtrace addresses>
  38
  39 --  Where:
  40 --  <target_arch> :
  41 --    selects the target architecture. In the absence of this parameter the
  42 --    default variant is chosen based on the Detect_Arch result. Generally,
  43 --    this parameter will only be used if vxaddr2line is recompiled manually.
  44 --    Otherwise, the command name will always be of the form
  45 --    <target>-vxaddr2line where there is no ambiguity on the target's
  46 --    architecture.
  47
  48 --  <exe_file> :
  49 --    The name of the partially linked binary file for the application.
  50
  51 --  <ref_address> :
  52 --    Runtime address (on the target) of a reference symbol you choose,
  53 --    which name shall match the value of the Ref_Symbol variable declared
  54 --    below. A symbol with a small offset from the beginning of the text
  55 --    segment is better, so "adainit" is a good choice.
  56
  57 --  <backtrace addresses> :
  58 --    The call chain addresses you obtained at run time on the target and
  59 --    for which you want a symbolic association.
  60
  61 --  TO ADD A NEW ARCHITECTURE add an appropriate value to Architecture type
  62 --  (in a format <host>_<target>), and then an appropriate value to Config_List
  63 --  array
  64
  65 with Ada.Text_IO;       use Ada.Text_IO;
  66 with Ada.Command_Line;  use Ada.Command_Line;
  67 with Ada.Strings.Fixed; use Ada.Strings.Fixed;
  68 with Interfaces;        use Interfaces;
  69
  70 with GNAT.OS_Lib;               use GNAT.OS_Lib;
  71 with GNAT.Directory_Operations; use GNAT.Directory_Operations;
  72 with GNAT.Expect;               use GNAT.Expect;
  73 with GNAT.Regpat;               use GNAT.Regpat;
  74
  75 procedure VxAddr2Line is
  76
  77    package Unsigned_32_IO is new Modular_IO (Unsigned_32);
  78    --  Instantiate Modular_IO to have Put
  79
  80    Ref_Symbol : constant String := "adainit";
  81    --  This is the name of the reference symbol which runtime address shall
  82    --  be provided as the <ref_address> argument.
  83
  84    --  All supported architectures
  85    type Architecture is
  86      (SOLARIS_I586,
  87       WINDOWS_POWERPC,
  88       WINDOWS_I586,
  89       WINDOWS_M68K,
  90       SOLARIS_POWERPC,
  91       DEC_ALPHA);
  92
  93    type Arch_Record is record
  94       Addr2line_Binary : String_Access;
  95       --  Name of the addr2line utility to use
  96
  97       Nm_Binary : String_Access;
  98       --  Name of the host nm utility, which will be used to find out the
  99       --  offset of the reference symbol in the text segment of the partially
 100       --  linked executable.
 101
 102       Addr_Digits_To_Skip : Integer;
 103       --  When addresses such as 0xfffffc0001dfed50 are provided, for instance
 104       --  on ALPHA, indicate the number of leading digits that can be ignored,
 105       --  which will avoid computational overflows. Typically only useful when
 106       --  64bit addresses are provided.
 107
 108       Bt_Offset_From_Call : Unsigned_32;
 109       --  Offset from a backtrace address to the address of the corresponding
 110       --  call instruction. This should always be 0, except on platforms where
 111       --  the backtrace addresses actually correspond to return and not call
 112       --  points. In such cases, a negative value is most likely.
 113    end record;
 114
 115    --  Configuration for each of the architectures
 116    Arch_List : array (Architecture'Range) of Arch_Record :=
 117      (WINDOWS_POWERPC =>
 118         (Addr2line_Binary    => null,
 119          Nm_Binary           => null,
 120          Addr_Digits_To_Skip => 0,
 121          Bt_Offset_From_Call => -4),
 122       WINDOWS_M68K =>
 123         (Addr2line_Binary    => null,
 124          Nm_Binary           => null,
 125          Addr_Digits_To_Skip => 0,
 126          Bt_Offset_From_Call => -4),
 127       WINDOWS_I586 =>
 128         (Addr2line_Binary    => null,
 129          Nm_Binary           => null,
 130          Addr_Digits_To_Skip => 0,
 131          Bt_Offset_From_Call => -2),
 132       SOLARIS_POWERPC =>
 133         (Addr2line_Binary    => null,
 134          Nm_Binary           => null,
 135          Addr_Digits_To_Skip => 0,
 136          Bt_Offset_From_Call => 0),
 137       SOLARIS_I586 =>
 138         (Addr2line_Binary    => null,
 139          Nm_Binary           => null,
 140          Addr_Digits_To_Skip => 0,
 141          Bt_Offset_From_Call => -2),
 142       DEC_ALPHA =>
 143         (Addr2line_Binary    => null,
 144          Nm_Binary           => null,
 145          Addr_Digits_To_Skip => 8,
 146          Bt_Offset_From_Call => 0)
 147      );
 148
 149    --  Current architecture
 150    Cur_Arch : Architecture;
 151
 152    --  State of architecture detection
 153    Detect_Success : Boolean := False;
 154
 155    -----------------------
 156    -- Local subprograms --
 157    -----------------------
 158
 159    procedure Error (Msg : String);
 160    pragma No_Return (Error);
 161    --  Prints the message and then terminates the program
 162
 163    procedure Usage;
 164    --  Displays the short help message and then terminates the program
 165
 166    function Get_Reference_Offset return Unsigned_32;
 167    --  Computes the static offset of the reference symbol by calling nm
 168
 169    function Get_Value_From_Hex_Arg (Arg : Natural) return Unsigned_32;
 170    --  Threats the argument number Arg as a C-style hexadecimal literal
 171    --  and returns its integer value
 172
 173    function Hex_Image (Value : Unsigned_32) return String_Access;
 174    --  Returns access to a string that contains hexadecimal image of Value
 175
 176    --  Separate functions that provide build-time customization:
 177
 178    procedure Detect_Arch;
 179    --  Saves in Cur_Arch the current architecture, based on the name of
 180    --  vxaddr2line instance and properties of the host. Detect_Success is False
 181    --  if detection fails
 182
 183    -----------------
 184    -- Detect_Arch --
 185    -----------------
 186
 187    procedure Detect_Arch is
 188       Name   : constant String := Base_Name (Command_Name);
 189       Proc   : constant String :=
 190                  Name (Name'First .. Index (Name, "-") - 1);
 191       Target : constant String :=
 192                  Name (Name'First .. Index (Name, "vxaddr2line") - 1);
 193
 194    begin
 195       Detect_Success := False;
 196
 197       if Proc = "" then
 198          return;
 199       end if;
 200
 201       if Proc = "alpha" then
 202          Cur_Arch := DEC_ALPHA;
 203       else
 204          --  Let's detect the host.
 205          --  ??? A naive implementation that can't distinguish between Unixes
 206          if Directory_Separator = '/' then
 207             Cur_Arch := Architecture'Value ("solaris_" & Proc);
 208          else
 209             Cur_Arch := Architecture'Value ("windows_" & Proc);
 210          end if;
 211       end if;
 212
 213       if Arch_List (Cur_Arch).Addr2line_Binary = null then
 214          Arch_List (Cur_Arch).Addr2line_Binary := new String'
 215            (Target & "addr2line");
 216       end if;
 217       if Arch_List (Cur_Arch).Nm_Binary = null then
 218          Arch_List (Cur_Arch).Nm_Binary := new String'
 219            (Target & "nm");
 220       end if;
 221
 222       Detect_Success := True;
 223
 224    exception
 225       when others =>
 226          return;
 227    end Detect_Arch;
 228
 229    -----------
 230    -- Error --
 231    -----------
 232
 233    procedure Error (Msg : String) is
 234    begin
 235       Put_Line (Msg);
 236       OS_Exit (1);
 237       raise Program_Error;
 238    end Error;
 239
 240    --------------------------
 241    -- Get_Reference_Offset --
 242    --------------------------
 243
 244    function Get_Reference_Offset return Unsigned_32 is
 245       Nm_Cmd  : constant String_Access :=
 246                   Locate_Exec_On_Path (Arch_List (Cur_Arch).Nm_Binary.all);
 247
 248       Nm_Args : constant Argument_List :=
 249                   (new String'("-P"),
 250                    new String'(Argument (1)));
 251
 252       Forever   : aliased String := "^@@@@";
 253       Reference : aliased String := Ref_Symbol & "\s+\S\s+([\da-fA-F]+)";
 254
 255       Pd     : Process_Descriptor;
 256       Result : Expect_Match;
 257
 258    begin
 259       --  If Nm is not found, abort
 260
 261       if Nm_Cmd = null then
 262          Error ("Couldn't find " & Arch_List (Cur_Arch).Nm_Binary.all);
 263       end if;
 264
 265       Non_Blocking_Spawn
 266         (Pd, Nm_Cmd.all, Nm_Args, Buffer_Size => 0, Err_To_Out => True);
 267
 268       --  Expect a string containing the reference symbol
 269
 270       Expect (Pd, Result,
 271               Regexp_Array'(1 => Reference'Unchecked_Access),
 272               Timeout => -1);
 273
 274       --  If we are here, the pattern was matched successfully
 275
 276       declare
 277          Match_String : constant String := Expect_Out_Match (Pd);
 278          Matches      : Match_Array (0 .. 1);
 279          Value        : Unsigned_32;
 280
 281       begin
 282          Match (Reference, Match_String, Matches);
 283          Value := Unsigned_32'Value
 284            ("16#"
 285             & Match_String (Matches (1).First .. Matches (1).Last) & "#");
 286
 287          --  Expect a string that will never be emitted, so that the
 288          --  process can be correctly terminated (with Process_Died)
 289
 290          Expect (Pd, Result,
 291                  Regexp_Array'(1 => Forever'Unchecked_Access),
 292                  Timeout => -1);
 293
 294       exception
 295          when Process_Died =>
 296             return Value;
 297       end;
 298
 299       --  We cannot get here
 300
 301       raise Program_Error;
 302
 303    exception
 304       when Invalid_Process =>
 305          Error ("Could not spawn a process " & Nm_Cmd.all);
 306
 307       when others    =>
 308
 309          --  The process died without matching the reference symbol or the
 310          --  format wasn't recognized.
 311
 312          Error ("Unexpected output from " & Nm_Cmd.all);
 313    end Get_Reference_Offset;
 314
 315    ----------------------------
 316    -- Get_Value_From_Hex_Arg --
 317    ----------------------------
 318
 319    function Get_Value_From_Hex_Arg (Arg : Natural) return Unsigned_32 is
 320       Cur_Arg : constant String := Argument (Arg);
 321       Offset  : Natural;
 322
 323    begin
 324       --  Skip "0x" prefix if present
 325
 326       if Cur_Arg'Length > 2 and then Cur_Arg (1 .. 2) = "0x" then
 327          Offset := 3;
 328       else
 329          Offset := 1;
 330       end if;
 331
 332       --  Add architecture-specific offset
 333
 334       Offset := Offset + Arch_List (Cur_Arch).Addr_Digits_To_Skip;
 335
 336       --  Convert to value
 337
 338       return Unsigned_32'Value
 339         ("16#" & Cur_Arg (Offset .. Cur_Arg'Last) & "#");
 340
 341    exception
 342       when Constraint_Error =>
 343
 344          Error ("Can't parse backtrace address '" & Cur_Arg & "'");
 345          raise;
 346    end Get_Value_From_Hex_Arg;
 347
 348    ---------------
 349    -- Hex_Image --
 350    ---------------
 351
 352    function Hex_Image (Value : Unsigned_32) return String_Access is
 353       Result    : String (1 .. 20);
 354       Start_Pos : Natural;
 355
 356    begin
 357       Unsigned_32_IO.Put (Result, Value, 16);
 358       Start_Pos := Index (Result, "16#") + 3;
 359       return new String'(Result (Start_Pos .. Result'Last - 1));
 360    end Hex_Image;
 361
 362    -----------
 363    -- Usage --
 364    -----------
 365
 366    procedure Usage is
 367    begin
 368       Put_Line ("Usage : " & Base_Name (Command_Name)
 369                 & " <executable> <"
 370                 & Ref_Symbol & " offset on target> <addr1> ...");
 371
 372       OS_Exit (1);
 373    end Usage;
 374
 375    Ref_Static_Offset, Ref_Runtime_Address, Bt_Address : Unsigned_32;
 376
 377    Addr2line_Cmd : String_Access;
 378
 379    Addr2line_Args : Argument_List (1 .. 501);
 380    --  We expect that there won't be more than 500 backtrace frames
 381
 382    Addr2line_Args_Count : Natural;
 383
 384    Success : Boolean;
 385
 386 --  Start of processing for VxAddr2Line
 387
 388 begin
 389
 390    Detect_Arch;
 391
 392    --  There should be at least two arguments
 393
 394    if Argument_Count < 2 then
 395       Usage;
 396    end if;
 397
 398    --  ??? HARD LIMIT! There should be at most 501 arguments
 399
 400    if Argument_Count > 501 then
 401       Error ("Too many backtrace frames");
 402    end if;
 403
 404    --  Do we have a valid architecture?
 405
 406    if not Detect_Success then
 407       Put_Line ("Couldn't detect the architecture");
 408       return;
 409    end if;
 410
 411    Addr2line_Cmd :=
 412      Locate_Exec_On_Path (Arch_List (Cur_Arch).Addr2line_Binary.all);
 413
 414    --  If Addr2line is not found, abort
 415
 416    if Addr2line_Cmd = null then
 417       Error ("Couldn't find " & Arch_List (Cur_Arch).Addr2line_Binary.all);
 418    end if;
 419
 420    --  The first argument specifies the image file. Check if it exists
 421
 422    if not Is_Regular_File (Argument (1)) then
 423       Error ("Couldn't find the executable " & Argument (1));
 424    end if;
 425
 426    --  The second argument specifies the reference symbol runtime address.
 427    --  Let's parse and store it
 428
 429    Ref_Runtime_Address := Get_Value_From_Hex_Arg (2);
 430
 431    --  Run nm command to get the reference symbol static offset
 432
 433    Ref_Static_Offset := Get_Reference_Offset;
 434
 435    --  Build addr2line parameters. First, the standard part
 436
 437    Addr2line_Args (1) := new String'("--exe=" & Argument (1));
 438    Addr2line_Args_Count := 1;
 439
 440    --  Now, append to this the adjusted backtraces in arguments 4 and further
 441
 442    for J in 3 .. Argument_Count loop
 443
 444       --  Basically, for each address in the runtime backtrace ...
 445
 446       --  o We compute its offset relatively to the runtime address of the
 447       --    reference symbol,
 448
 449       --  and then ...
 450
 451       --  o We add this offset to the static one for the reference symbol in
 452       --    the executable to find the executable offset corresponding to the
 453       --    backtrace address.
 454
 455       Bt_Address := Get_Value_From_Hex_Arg (J);
 456
 457       Bt_Address :=
 458         Bt_Address - Ref_Runtime_Address
 459                    + Ref_Static_Offset
 460                    + Arch_List (Cur_Arch).Bt_Offset_From_Call;
 461
 462       Addr2line_Args_Count := Addr2line_Args_Count + 1;
 463       Addr2line_Args (Addr2line_Args_Count) := Hex_Image (Bt_Address);
 464    end loop;
 465
 466    --  Run the resulting command
 467
 468    Spawn (Addr2line_Cmd.all,
 469           Addr2line_Args (1 .. Addr2line_Args_Count), Success);
 470
 471    if not Success then
 472       Error ("Couldn't spawn " & Addr2line_Cmd.all);
 473    end if;
 474
 475 exception
 476    when others =>
 477
 478       --  Mask all exceptions
 479
 480       return;
 481 end VxAddr2Line;