# Copyright 2002, 2003, 2004, 2007, 2008, 2009, 2010 # Free Software Foundation, Inc. # This program is free software; you can redistribute it and/or modify # it under the terms of the GNU General Public License as published by # the Free Software Foundation; either version 3 of the License, or # (at your option) any later version. # # This program is distributed in the hope that it will be useful, # but WITHOUT ANY WARRANTY; without even the implied warranty of # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the # GNU General Public License for more details. # # You should have received a copy of the GNU General Public License # along with this program. If not, see . # This file is part of the gdb testsuite # Test casting, especially between class types or pointer-to-class # types. # This file is part of the gdb testsuite if $tracelevel then { strace $tracelevel } # # test running programs # set prms_id 0 set bug_id 0 if { [skip_cplus_tests] } { continue } set testfile "casts" set srcfile ${testfile}.cc set binfile ${objdir}/${subdir}/${testfile} if [get_compiler_info ${binfile} "c++"] { return -1; } if { [gdb_compile "${srcdir}/${subdir}/${srcfile}" "${binfile}" executable {debug c++}] != "" } { untested casts.exp return -1 } gdb_exit gdb_start gdb_reinitialize_dir $srcdir/$subdir gdb_load ${binfile} if ![runto_main] then { perror "couldn't run to breakpoint" continue } gdb_test "break [gdb_get_line_number "casts.exp: 1"]" \ "Breakpoint.*at.* file .*" \ "" gdb_test "continue" "Breakpoint .* at .*casts.cc.*" "" # Casting a pointer to a base class to a pointer to a derived class # should yield the entire derived class. Until August 2002, GDB got # the enclosing type on `(B *) a' wrong: while the value's static type # was `B *', as it should be, the enclosing type (which is supposed to # be the dynamic type) was `A *'. It's senseless to have a static # type derived from the dynamic type; it should be the other way # 'round. Dereferencing this oddly typed pointer yielded a value in # which only the base class's members were initialized, since GDB uses # the enclosing type to decide how many bytes to read. Members from # the derived class were garbage, from GDB's address space. gdb_test "print * (B *) a" ".* = { = {a = 42}, b = 1729}" \ "cast base class pointer to derived class pointer" # Check also that we get the same results from letting the compiler do # the dereference. gdb_test "print * b" ".* = { = {a = 42}, b = 1729}" \ "let compiler cast base class pointer to derived class pointer" # Check upcasting (it is trivial but still). gdb_test "print * (A *) b" ".* = {a = 42}" \ "cast derived class pointer to base class pointer" # Casting References. # Check upcasting. gdb_test "print (A &) br" ".* = .A &.* {a = 42}" \ "cast derived class reference to base class reference" # Check downcasting. gdb_test "print (B &) ar" ".* = .B.* { = {a = 42}, b = 1729}" \ "cast base class reference to derived class reference" # Check compiler casting gdb_test "print br" ".* = .B.* { = {a = 42}, b = 1729}" \ "let compiler cast base class reference to derived class reference"