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) 2002-2004 Ada Core Technologies, 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,  59 Temple Place - Suite 330,  Boston, --
  20 -- MA 02111-1307, USA.                                                      --
  21 --                                                                          --
  22 -- GNAT was originally developed  by the GNAT team at  New York University. --
  23 -- Extensive contributions were provided by Ada Core Technologies Inc.      --
  24 --                                                                          --
  25 ------------------------------------------------------------------------------
  26
  27 --  This program is meant to be used with vxworks to compute symbolic
  28 --  backtraces on the host from non-symbolic backtraces obtained on the target.
  29
  30 --  The basic idea is to automate the computation of the necessary address
  31 --  adjustments prior to calling addr2line when the application has only been
  32 --  partially linked on the host.
  33
  34 --  Variants for various targets are supported, and the command line should
  35 --  be like :
  36
  37 --  <target>-addr2line [-a <target_arch>] <exe_file> <ref_address>
  38 --                     <backtrace addresses>
  39
  40 --  Where:
  41 --  <target_arch> :
  42 --    selects the target architecture. In the absence of this parameter the
  43 --    default variant is chosen based on the Detect_Arch result. Generally,
  44 --    this parameter will only be used if vxaddr2line is recompiled manually.
  45 --    Otherwise, the command name will always be of the form
  46 --    <target>-vxaddr2line where there is no ambiguity on the target's
  47 --    architecture.
  48
  49 --  <exe_file> :
  50 --    The name of the partially linked binary file for the application.
  51
  52 --  <ref_address> :
  53 --    Runtime address (on the target) of a reference symbol you choose,
  54 --    which name shall match the value of the Ref_Symbol variable declared
  55 --    below. A symbol with a small offset from the beginning of the text
  56 --    segment is better, so "adainit" is a good choice.
  57
  58 --  <backtrace addresses> :
  59 --    The call chain addresses you obtained at run time on the target and
  60 --    for which you want a symbolic association.
  61
  62 --  TO ADD A NEW ARCHITECTURE add an appropriate value to Architecture type
  63 --  (in a format <host>_<target>), and then an appropriate value to Config_List
  64 --  array
  65
  66 with Text_IO;             use Text_IO;
  67 with Ada.Integer_Text_IO; use Ada.Integer_Text_IO;
  68 with Ada.Command_Line;    use Ada.Command_Line;
  69 with Ada.Strings.Fixed;   use Ada.Strings.Fixed;
  70
  71 with GNAT.OS_Lib; use GNAT.OS_Lib;
  72 with GNAT.Directory_Operations; use GNAT.Directory_Operations;
  73 with GNAT.Expect; use GNAT.Expect;
  74 with GNAT.Regpat; use GNAT.Regpat;
  75
  76 procedure VxAddr2Line is
  77
  78    Ref_Symbol : constant String := "adainit";
  79    --  This is the name of the reference symbol which runtime address shall
  80    --  be provided as the <ref_address> argument.
  81
  82    --  All supported architectures
  83    type Architecture is
  84      (SOLARIS_I586,
  85       WINDOWS_POWERPC,
  86       WINDOWS_M68K,
  87       SOLARIS_POWERPC,
  88       DEC_ALPHA);
  89
  90    type Arch_Record is record
  91       Addr2line_Binary : String_Access;
  92       --  Name of the addr2line utility to use.
  93
  94       Nm_Binary : String_Access;
  95       --  Name of the host nm utility, which will be used to find out the
  96       --  offset of the reference symbol in the text segment of the partially
  97       --  linked executable.
  98
  99       Addr_Digits_To_Skip : Integer;
 100       --  When addresses such as 0xfffffc0001dfed50 are provided, for instance
 101       --  on ALPHA, indicate the number of leading digits that can be ignored,
 102       --  which will avoid computational overflows. Typically only useful when
 103       --  64bit addresses are provided.
 104
 105       Bt_Offset_From_Call : Integer;
 106       --  Offset from a backtrace address to the address of the corresponding
 107       --  call instruction. This should always be 0, except on platforms where
 108       --  the backtrace addresses actually correspond to return and not call
 109       --  points. In such cases, a negative value is most likely.
 110    end record;
 111
 112    --  Configuration for each of the architectures
 113    Arch_List : array (Architecture'Range) of Arch_Record :=
 114      (WINDOWS_POWERPC =>
 115         (Addr2line_Binary    => null,
 116          Nm_Binary           => null,
 117          Addr_Digits_To_Skip => 0,
 118          Bt_Offset_From_Call => -4),
 119       WINDOWS_M68K =>
 120         (Addr2line_Binary    => null,
 121          Nm_Binary           => null,
 122          Addr_Digits_To_Skip => 0,
 123          Bt_Offset_From_Call => -4),
 124       SOLARIS_POWERPC =>
 125         (Addr2line_Binary    => null,
 126          Nm_Binary           => null,
 127          Addr_Digits_To_Skip => 0,
 128          Bt_Offset_From_Call => 0),
 129       SOLARIS_I586 =>
 130         (Addr2line_Binary    => null,
 131          Nm_Binary           => null,
 132          Addr_Digits_To_Skip => 0,
 133          Bt_Offset_From_Call => -2),
 134       DEC_ALPHA =>
 135         (Addr2line_Binary    => null,
 136          Nm_Binary           => null,
 137          Addr_Digits_To_Skip => 8,
 138          Bt_Offset_From_Call => 0)
 139      );
 140
 141    --  Current architecture
 142    Cur_Arch : Architecture;
 143
 144    --  State of architecture detection
 145    Detect_Success : Boolean := False;
 146
 147    -----------------------
 148    -- Local subprograms --
 149    -----------------------
 150
 151    procedure Error (Msg : String);
 152    pragma No_Return (Error);
 153    --  Prints the message and then terminates the program
 154
 155    procedure Usage;
 156    --  Displays the short help message and then terminates the program
 157
 158    function Get_Reference_Offset return Integer;
 159    --  Computes the static offset of the reference symbol by calling nm
 160
 161    function Get_Value_From_Hex_Arg (Arg : Natural) return Integer;
 162    --  Threats the argument number Arg as a C-style hexadecimal literal
 163    --  and returns its integer value
 164
 165    function Hex_Image (Value : Integer) return String_Access;
 166    --  Returns access to a string that contains hexadecimal image of Value
 167
 168    --  Separate functions that provide build-time customization:
 169
 170    procedure Detect_Arch;
 171    --  Saves in Cur_Arch the current architecture, based on the name of
 172    --  vxaddr2line instance and properties of the host. Detect_Success is False
 173    --  if detection fails
 174
 175    -----------------
 176    -- Detect_Arch --
 177    -----------------
 178
 179    procedure Detect_Arch is
 180       Name   : constant String := Base_Name (Command_Name);
 181       Proc   : constant String :=
 182                  Name (Name'First .. Index (Name, "-") - 1);
 183       Target : constant String :=
 184                  Name (Name'First .. Index (Name, "vxaddr2line") - 1);
 185
 186    begin
 187       Detect_Success := False;
 188
 189       if Proc = "" then
 190          return;
 191       end if;
 192
 193       if Proc = "alpha" then
 194          Cur_Arch := DEC_ALPHA;
 195       else
 196          --  Let's detect the host.
 197          --  ??? A naive implementation that can't distinguish between Unixes
 198          if Directory_Separator = '/' then
 199             Cur_Arch := Architecture'Value ("solaris_" & Proc);
 200          else
 201             Cur_Arch := Architecture'Value ("windows_" & Proc);
 202          end if;
 203       end if;
 204
 205       if Arch_List (Cur_Arch).Addr2line_Binary = null then
 206          Arch_List (Cur_Arch).Addr2line_Binary := new String'
 207            (Target & "addr2line");
 208       end if;
 209       if Arch_List (Cur_Arch).Nm_Binary = null then
 210          Arch_List (Cur_Arch).Nm_Binary := new String'
 211            (Target & "nm");
 212       end if;
 213
 214       Detect_Success := True;
 215
 216    exception
 217       when others =>
 218          return;
 219    end Detect_Arch;
 220
 221    -----------
 222    -- Error --
 223    -----------
 224
 225    procedure Error (Msg : String) is
 226    begin
 227       Put_Line (Msg);
 228       OS_Exit (1);
 229       raise Program_Error;
 230    end Error;
 231
 232    --------------------------
 233    -- Get_Reference_Offset --
 234    --------------------------
 235
 236    function Get_Reference_Offset return Integer is
 237       Nm_Cmd  : constant String_Access :=
 238                   Locate_Exec_On_Path (Arch_List (Cur_Arch).Nm_Binary.all);
 239
 240       Nm_Args : constant Argument_List :=
 241                   (new String'("-P"),
 242                    new String'(Argument (1)));
 243
 244       Forever   : aliased String := "^@@@@";
 245       Reference : aliased String := Ref_Symbol & "\s+\S\s+([\da-fA-F]+)";
 246
 247       Pd     : Process_Descriptor;
 248       Result : Expect_Match;
 249
 250    begin
 251       --  If Nm is not found, abort
 252
 253       if Nm_Cmd = null then
 254          Error ("Couldn't find " & Arch_List (Cur_Arch).Nm_Binary.all);
 255       end if;
 256
 257       Non_Blocking_Spawn
 258         (Pd, Nm_Cmd.all, Nm_Args, Buffer_Size => 0, Err_To_Out => True);
 259
 260       --  Expect a string containing the reference symbol
 261
 262       Expect (Pd, Result,
 263               Regexp_Array'(1 => Reference'Unchecked_Access),
 264               Timeout => -1);
 265
 266       --  If we are here, the pattern was matched successfully
 267
 268       declare
 269          Match_String : constant String := Expect_Out_Match (Pd);
 270          Matches      : Match_Array (0 .. 1);
 271          Value        : Integer;
 272
 273       begin
 274          Match (Reference, Match_String, Matches);
 275          Value := Integer'Value
 276            ("16#"
 277             & Match_String (Matches (1).First .. Matches (1).Last) & "#");
 278
 279          --  Expect a string that will never be emitted, so that the
 280          --  process can be correctly terminated (with Process_Died)
 281
 282          Expect (Pd, Result,
 283                  Regexp_Array'(1 => Forever'Unchecked_Access),
 284                  Timeout => -1);
 285
 286       exception
 287          when Process_Died =>
 288             return Value;
 289       end;
 290
 291       --  We can not get here
 292
 293       raise Program_Error;
 294
 295    exception
 296       when Invalid_Process =>
 297          Error ("Could not spawn a process " & Nm_Cmd.all);
 298
 299       when others    =>
 300
 301          --  The process died without matching the reference symbol or the
 302          --  format wasn't recognized.
 303
 304          Error ("Unexpected output from " & Nm_Cmd.all);
 305    end Get_Reference_Offset;
 306
 307    ----------------------------
 308    -- Get_Value_From_Hex_Arg --
 309    ----------------------------
 310
 311    function Get_Value_From_Hex_Arg (Arg : Natural) return Integer is
 312       Cur_Arg : constant String := Argument (Arg);
 313       Offset  : Natural;
 314
 315    begin
 316       --  Skip "0x" prefix if present
 317
 318       if Cur_Arg'Length > 2 and then Cur_Arg (1 .. 2) = "0x" then
 319          Offset := 3;
 320       else
 321          Offset := 1;
 322       end if;
 323
 324       --  Add architecture-specific offset
 325
 326       Offset := Offset + Arch_List (Cur_Arch).Addr_Digits_To_Skip;
 327
 328       --  Convert to value
 329
 330       return Integer'Value ("16#" & Cur_Arg (Offset .. Cur_Arg'Last) & "#");
 331    end Get_Value_From_Hex_Arg;
 332
 333    ---------------
 334    -- Hex_Image --
 335    ---------------
 336
 337    function Hex_Image (Value : Integer) return String_Access is
 338       Result    : String (1 .. 20);
 339       Start_Pos : Natural;
 340
 341    begin
 342       Put (Result, Value, 16);
 343       Start_Pos := Index (Result, "16#") + 3;
 344       return new String'(Result (Start_Pos .. Result'Last - 1));
 345    end Hex_Image;
 346
 347    -----------
 348    -- Usage --
 349    -----------
 350
 351    procedure Usage is
 352    begin
 353       Put_Line ("Usage : " & Base_Name (Command_Name)
 354                 & " <executable> <"
 355                 & Ref_Symbol & " offset on target> <addr1> ...");
 356
 357       OS_Exit (1);
 358    end Usage;
 359
 360    Ref_Static_Offset, Ref_Runtime_Address, Bt_Address : Integer;
 361
 362    Addr2line_Cmd : String_Access;
 363
 364    Addr2line_Args : Argument_List (1 .. 501);
 365    --  We expect that there won't be more than 500 backtrace frames
 366
 367    Addr2line_Args_Count : Natural;
 368
 369    Success : Boolean;
 370
 371 --  Start of processing for VxAddr2Line
 372
 373 begin
 374
 375    Detect_Arch;
 376
 377    --  There should be at least two arguments
 378
 379    if Argument_Count < 2 then
 380       Usage;
 381    end if;
 382
 383    --  ??? HARD LIMIT! There should be at most 501 arguments
 384
 385    if Argument_Count > 501 then
 386       Error ("Too many backtrace frames");
 387    end if;
 388
 389    --  Do we have a valid architecture?
 390
 391    if not Detect_Success then
 392       Put_Line ("Couldn't detect the architecture");
 393       return;
 394    end if;
 395
 396    Addr2line_Cmd :=
 397      Locate_Exec_On_Path (Arch_List (Cur_Arch).Addr2line_Binary.all);
 398
 399    --  If Addr2line is not found, abort
 400
 401    if Addr2line_Cmd = null then
 402       Error ("Couldn't find " & Arch_List (Cur_Arch).Addr2line_Binary.all);
 403    end if;
 404
 405    --  The first argument specifies the image file. Check if it exists.
 406
 407    if not Is_Regular_File (Argument (1)) then
 408       Error ("Couldn't find the executable " & Argument (1));
 409    end if;
 410
 411    --  The second argument specifies the reference symbol runtime address.
 412    --  Let's parse and store it
 413
 414    Ref_Runtime_Address := Get_Value_From_Hex_Arg (2);
 415
 416    --  Run nm command to get the reference symbol static offset
 417
 418    Ref_Static_Offset := Get_Reference_Offset;
 419
 420    --  Build addr2line parameters. First, the standard part
 421
 422    Addr2line_Args (1) := new String'("--exe=" & Argument (1));
 423    Addr2line_Args_Count := 1;
 424
 425    --  Now, append to this the adjusted backtraces in arguments 4 and further
 426
 427    for J in 3 .. Argument_Count loop
 428
 429       --  Basically, for each address in the runtime backtrace ...
 430
 431       --  o We compute its offset relatively to the runtime address of the
 432       --    reference symbol,
 433
 434       --  and then ...
 435
 436       --  o We add this offset to the static one for the reference symbol in
 437       --    the executable to find the executable offset corresponding to the
 438       --    backtrace address.
 439
 440       Bt_Address := Get_Value_From_Hex_Arg (J);
 441
 442       Bt_Address :=
 443         Bt_Address - Ref_Runtime_Address
 444                    + Ref_Static_Offset
 445                    + Arch_List (Cur_Arch).Bt_Offset_From_Call;
 446
 447       Addr2line_Args_Count := Addr2line_Args_Count + 1;
 448       Addr2line_Args (Addr2line_Args_Count) := Hex_Image (Bt_Address);
 449    end loop;
 450
 451    --  Run the resulting command
 452
 453    Spawn (Addr2line_Cmd.all,
 454           Addr2line_Args (1 .. Addr2line_Args_Count), Success);
 455
 456 exception
 457    when others =>
 458
 459       --  Mask all exceptions
 460
 461       return;
 462 end VxAddr2Line;