gnu/dist/gdb6/gdb/testsuite/gdb.cp/casts.exp

   1 # Copyright 2002, 2003, 2004 Free Software Foundation, Inc.
   2
   3 # This program is free software; you can redistribute it and/or modify
   4 # it under the terms of the GNU General Public License as published by
   5 # the Free Software Foundation; either version 2 of the License, or
   6 # (at your option) any later version.
   7 #
   8 # This program is distributed in the hope that it will be useful,
   9 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  10 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11 # GNU General Public License for more details.
  12 #
  13 # You should have received a copy of the GNU General Public License
  14 # along with this program; if not, write to the Free Software
  15 # Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  16
  17 # This file is part of the gdb testsuite
  18
  19 # Test casting, especially between class types or pointer-to-class
  20 # types.
  21
  22 # This file is part of the gdb testsuite
  23
  24 if $tracelevel then {
  25         strace $tracelevel
  26         }
  27
  28 #
  29 # test running programs
  30 #
  31
  32 set prms_id 0
  33 set bug_id 0
  34
  35 if { [skip_cplus_tests] } { continue }
  36
  37 set testfile "casts"
  38 set srcfile ${testfile}.cc
  39 set binfile ${objdir}/${subdir}/${testfile}
  40
  41 if [get_compiler_info ${binfile} "c++"] {
  42     return -1;
  43 }
  44
  45 if  { [gdb_compile "${srcdir}/${subdir}/${srcfile}" "${binfile}" executable {debug c++}] != "" } {
  46      gdb_suppress_entire_file "Testcase compile failed, so all tests in this file will automatically fail."
  47 }
  48
  49
  50 gdb_exit
  51 gdb_start
  52 gdb_reinitialize_dir $srcdir/$subdir
  53 gdb_load ${binfile}
  54
  55 if ![runto_main] then {
  56     perror "couldn't run to breakpoint"
  57     continue
  58 }
  59
  60 gdb_test "break [gdb_get_line_number "casts.exp: 1"]" \
  61     "Breakpoint.*at.* file .*" \
  62     ""
  63
  64 gdb_test "continue" "Breakpoint .* at .*casts.cc.*" ""
  65
  66 # Casting a pointer to a base class to a pointer to a derived class
  67 # should yield the entire derived class.  Until August 2002, GDB got
  68 # the enclosing type on `(B *) a' wrong: while the value's static type
  69 # was `B *', as it should be, the enclosing type (which is supposed to
  70 # be the dynamic type) was `A *'.  It's senseless to have a static
  71 # type derived from the dynamic type; it should be the other way
  72 # 'round.  Dereferencing this oddly typed pointer yielded a value in
  73 # which only the base class's members were initialized, since GDB uses
  74 # the enclosing type to decide how many bytes to read.  Members from
  75 # the derived class were garbage, from GDB's address space.
  76 gdb_test "print * (B *) a" ".* = {<A> = {a = 42}, b = 1729}" \
  77     "cast base class pointer to derived class pointer"
  78
  79 # Check also that we get the same results from letting the compiler do
  80 # the dereference.
  81 gdb_test "print * b" ".* = {<A> = {a = 42}, b = 1729}" \
  82     "let compiler cast base class pointer to derived class pointer"