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Upon trying to print the value of a variant record, a user noticed
the following problem:
(gdb) print rt
warning: Unknown upper bound, using 1.
warning: Unknown upper bound, using 1.
$1 = (a => ((a1 => (4), a2 => (4)), (a1 => (8), a2 => (8))))
The expected output is:
(gdb) print rt
$1 = (a => ((a1 => (4, 4), a2 => (8, 8)), (a1 => (4, 4),
a2 => (8, 8))))
The problems comes from the fact that components "a1" and "a2" are
defined as arrays whose upper bound is dynamic. To determine the value
of that upper bound, GDB relies on the GNAT encoding and searches
for the parallel ___U variable. Unfortunately, the search fails
while doing a binary search inside the partial symtab of the unit
where the array and its bound (and therefore the parallel ___U variable)
are defined.
It fails because partial symbols are sorted using strcmp_iw_ordered,
while Ada symbol lookups are performed using a different comparison
function (ada-lang.c:compare_names). The two functions are supposed
to be compatible, but a change performed in April 2011 modified
strcmp_iw_ordered, introducing case-sensitivity issues. As a result,
the two functions would now disagree when passed the following
two arguments:
string1="common__inner_arr___SIZE_A_UNIT"
string2="common__inner_arr__T4s___U"
The difference starts at "_SIZE_A_UNIT" vs "T4s___U". So, it's mostly
a matter of comparing '_' with 'T'.
On the one hand, strcmp_iw_ordered would return -1, while compare_names
returned 11. The change that made all the difference is that
strcmp_iw_ordered now performs a case-insensitive comparison,
and only resorts to case-sentitive comparison if the first comparison
finds an equality. This changes everything, because while 'T' (84)
and 't' (116) are on opposite sides of '_' (95).
This patch aims at restoring the compatibility between the two
functions, by adding case-sensitivity handling in the Ada comparison
function.
gdb/ChangeLog:
* ada-lang.c (compare_names_with_case): Renamed from
compare_names, adding a new parameter "casing" and its handling.
New function documentation.
(compare_names): New function, implemented using
compare_names_with_case.
README for GNU development tools This directory contains various GNU compilers, assemblers, linkers, debuggers, etc., plus their support routines, definitions, and documentation. If you are receiving this as part of a GDB release, see the file gdb/README. If with a binutils release, see binutils/README; if with a libg++ release, see libg++/README, etc. That'll give you info about this package -- supported targets, how to use it, how to report bugs, etc. It is now possible to automatically configure and build a variety of tools with one command. To build all of the tools contained herein, run the ``configure'' script here, e.g.: ./configure make To install them (by default in /usr/local/bin, /usr/local/lib, etc), then do: make install (If the configure script can't determine your type of computer, give it the name as an argument, for instance ``./configure sun4''. You can use the script ``config.sub'' to test whether a name is recognized; if it is, config.sub translates it to a triplet specifying CPU, vendor, and OS.) If you have more than one compiler on your system, it is often best to explicitly set CC in the environment before running configure, and to also set CC when running make. For example (assuming sh/bash/ksh): CC=gcc ./configure make A similar example using csh: setenv CC gcc ./configure make Much of the code and documentation enclosed is copyright by the Free Software Foundation, Inc. See the file COPYING or COPYING.LIB in the various directories, for a description of the GNU General Public License terms under which you can copy the files. REPORTING BUGS: Again, see gdb/README, binutils/README, etc., for info on where and how to report problems.