1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
|
# 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 <http://www.gnu.org/licenses/>.
# 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> = {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> = {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> = {a = 42}, b = 1729}" \
"cast base class reference to derived class reference"
# Check compiler casting
gdb_test "print br" ".* = .B.* {<A> = {a = 42}, b = 1729}" \
"let compiler cast base class reference to derived class reference"
|
