0e2da9f013
Consider the following code, which declares a variabled called "input"
of type "parameter", which is a record with one component called "u2",
where the type of that component is a simple 3-element array of
floating point values:
type Float_Array_3 is array (1 .. 3) of Float;
type parameters is record
u2 : Float_Array_3;
end record;
input : parameters;
Trying to assign a value to input.u2 causes GDB to crash:
(gdb) p input.u2 := (0.25,0.5,0.75)
[1] 20228 segmentation fault (core dumped) [...]/gdb
The crash occurs because input.u2 is described in the debugging
info as a typedef of an array. Indeed, input's type is:
<1><ae9>: Abbrev Number: 7 (DW_TAG_structure_type)
<aea> DW_AT_name : (indirect string, offset: 0x1045): target_wrapper__parameters
[...]
<2><af5>: Abbrev Number: 8 (DW_TAG_member)
<af6> DW_AT_name : u2
[...]
<afb> DW_AT_type : <0xaca>
and, looking at DIE 0xaca to get input.u2's type, we see:
<1><aca>: Abbrev Number: 4 (DW_TAG_typedef)
<acb> DW_AT_name : (indirect string, offset: 0x1060): target_wrapper__float_array_3
[...]
<ad1> DW_AT_type : <0xad5>
We can also confirm, following the DW_AT_type attribute (0xad5), that
it's a typedef of our array:
<1><ad5>: Abbrev Number: 5 (DW_TAG_array_type)
<ad6> DW_AT_name : (indirect string, offset: 0x1060): target_wrapper__float_array_3
[...]
In fact, this scenario uncovered 2 areas where typedef handling
is missing, thus causing a crash. The first happens inside
assign_aggregate:
if (ada_is_direct_array_type (lhs_type))
{
lhs = ada_coerce_to_simple_array (lhs);
lhs_type = value_type (lhs);
low_index = TYPE_ARRAY_LOWER_BOUND_VALUE (lhs_type);
high_index = TYPE_ARRAY_UPPER_BOUND_VALUE (lhs_type);
}
Here, lhs_type is a TYPE_CODE_TYPEDEF. ada_is_direct_array_type
knows how to handle it, but TYPE_ARRAY_LOWER_BOUND_VALUE assumes
that the given type is a TYPE_CODE_ARRAY. As such, it ends up
accessing some fields in lhs_type which it shouldn't, and kaboom.
We fixed this issue by making sure that the TYPE_CODE_TYPEDEF
layer gets stripped.
Once this is done, we hit a different kind of error, also leading to
a SEGV, this time in assign_component. The code looks like this:
if (TYPE_CODE (value_type (lhs)) == TYPE_CODE_ARRAY)
[...]
else
[...]
Because once again lhs is a TYPE_CODE_TYPEDEF, the check fail,
and we end up assuming that lhs is a struct, executing the "else"
block, which is:
else
{
elt = ada_index_struct_field (index, lhs, 0, value_type (lhs));
elt = ada_to_fixed_value (elt);
}
Since lhs is not a struct, ada_index_struct_field returns NULL,
which ada_to_fixed_value does not handle well, hence another crash.
This patch fixes this other issue the same way, by stripping
TYPE_CODE_TYPEDEF layers.
gdb/ChangeLog:
* ada-lang.c (assign_component): Strip any TYPE_CODE_TYPEDEF
layer from lhs' type.
(assign_aggregate): Likewise.
gdb/testsuite:
* gdb.ada/assign_arr: New testcase.
Tested on x86_64-linux.
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| bfd | ||
| binutils | ||
| config | ||
| cpu | ||
| elfcpp | ||
| etc | ||
| gas | ||
| gdb | ||
| gold | ||
| gprof | ||
| include | ||
| intl | ||
| ld | ||
| libdecnumber | ||
| libiberty | ||
| opcodes | ||
| readline | ||
| sim | ||
| texinfo | ||
| zlib | ||
| .cvsignore | ||
| .gitattributes | ||
| .gitignore | ||
| ChangeLog | ||
| compile | ||
| config-ml.in | ||
| config.guess | ||
| config.rpath | ||
| config.sub | ||
| configure | ||
| configure.ac | ||
| COPYING | ||
| COPYING3 | ||
| COPYING3.LIB | ||
| COPYING.LIB | ||
| COPYING.LIBGLOSS | ||
| COPYING.NEWLIB | ||
| depcomp | ||
| djunpack.bat | ||
| install-sh | ||
| libtool.m4 | ||
| lt~obsolete.m4 | ||
| ltgcc.m4 | ||
| ltmain.sh | ||
| ltoptions.m4 | ||
| ltsugar.m4 | ||
| ltversion.m4 | ||
| MAINTAINERS | ||
| Makefile.def | ||
| Makefile.in | ||
| Makefile.tpl | ||
| makefile.vms | ||
| missing | ||
| mkdep | ||
| mkinstalldirs | ||
| move-if-change | ||
| README | ||
| README-maintainer-mode | ||
| setup.com | ||
| src-release.sh | ||
| symlink-tree | ||
| ylwrap | ||
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.