c1b5a1a6e7
Trying to print the value of a string whose size is not known at
compile-time before it gets assigned a value can lead to the following
internal error:
(gdb) p my_str
$1 =
/[...]/utils.c:1089: internal-error: virtual memory exhausted.
What happens is that my_str is described as a reference to an array
type whose bounds are dynamic. During the read of that variable's
value (in default_read_var_value), we end up resolving dynamic types
which, for reference types, makes us also resolve the target of that
reference type. This means we resolve our variable to a reference
to an array whose bounds are undefined, and unfortunately very far
appart.
So, when we pass that value to ada-valprint, and in particular to
da_val_print_ref, we eventually try to allocate too large of a buffer
corresponding to the (bogus) size of our array, hence the internal
error.
This patch fixes the problem by adding a size_check before trying
to print the dereferenced value. To perform this check, a function
that was previously specific to ada-lang.c (check_size) gets
exported, and renamed to something less prone to name collisions
(ada_ensure_varsize_limit).
gdb/ChangeLog:
* ada-lang.h (ada_ensure_varsize_limit): Declare.
* ada-lang.c (check_size): Remove advance declaration.
(ada_ensure_varsize_limit): Renames check_size.
Replace calls to check_size by calls to ada_ensure_varsize_limit
throughout.
* ada-valprint.c (ada_val_print_ref): Add call to
ada_ensure_varsize_limit. Add comment explaining why.
gdb/testsuite/ChangeLog:
* gdb.ada/str_uninit: New testcase.
40 lines
1.4 KiB
Text
40 lines
1.4 KiB
Text
# Copyright 2014 Free Software Foundation, Inc.
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#
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# This program is free software; you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation; either version 3 of the License, or
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# (at your option) any later version.
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#
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with this program. If not, see <http://www.gnu.org/licenses/>.
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load_lib "ada.exp"
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standard_ada_testfile parse
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if {[gdb_compile_ada "${srcfile}" "${binfile}" executable [list debug ]] != "" } {
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return -1
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}
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clean_restart ${testfile}
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set bp_location [gdb_get_line_number "START" ${testdir}/parse.adb]
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if ![runto "parse.adb:$bp_location" ] then {
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perror "Couldn't run ${testfile}"
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return
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}
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# Print MY_STR. Since the string has not been initialized, including
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# its bounds, anything can happen, including an error. The purpose
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# of this test is just to verify that we do not get an _internal_
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# error.
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gdb_test "print my_str" " = .*"
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# Just to be certain that the debugger is really still alive,
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# try printing something really simple.
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gdb_test "print 1235813" " = 1235813"
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