binutils-gdb modified for the FreeChainXenon project
![]() Trying to print a packed array sometimes leads to a crash (see attached testcase for an example of when this happens): | (gdb) p bad | [1] 65571 segmentation fault gdb -q foo Variable "bad" is declared in the debug information as an array where the array's type name has an XPnnn suffix: | .uleb128 0xc # (DIE (0x566) DW_TAG_typedef) | .long .LASF200 # DW_AT_name: "pck__t___XP1" | [loc info attributes snipped] | .long 0x550 # DW_AT_type | .byte 0x1 # DW_AT_alignment The signals to GDB that the debugging information follows a GNAT encoding used for packed arrays, and an in order to decode it, we need to find the type whose name is the same minus the "___XPnnn" suffix: "pck__t". For that, we make a call to ada-lang.c::standard_lookup, which is a simple function which essentially does: | /* Return the result of a standard (literal, C-like) lookup of NAME in | given DOMAIN, visible from lexical block BLOCK. */ | | [...] | sym = lookup_symbol_in_language (name, block, domain, language_c, 0); Unfortunately for us, while the intent of this call was to perform an exact-match lookup, in our case, it returns ... type pck__t___XP1 instead! In other words, it finds itself back. The reason why it finds this type is a confluence of two factors: (1) Forcing the lookup into language_c currently does not affect how symbol matching is done anymore, because we look at the symbol's language to determine which kind of matching should be done; (2) The lookup searches the local context (via block) first, beforei doing a more general lookup. And looking at the debug info for the main subprogram, we see that type "pck__t" is not declared there, only in the debug info for pck.ads. In other words, there is no way that we accidently find "pck__t" by random chance. I believe Pedro added a new function called ada_lookup_encoded_symbol for that specific purpose, so I started by replacing the lookup by language above by this. Unfortunately, still no joy. This was because, even though ada_lookup_encoded_symbol puts angle- brackets around the search name to signal that we want a verbatim search, we end up losing that information in the function called to compare a symbol with the search name: | static bool | do_full_match (const char *symbol_search_name, | const lookup_name_info &lookup_name, | completion_match_result *comp_match_res) | { | return full_match (symbol_search_name, ada_lookup_name (lookup_name)); ^^^^^^^^^^^^^^^ | <=> lookup_name.m_ada.m_encoded_name (no angle brackets) The way I fixed this was by introducing a new function called do_exact_match, and then adjust ada_get_symbol_name_matcher to return that function when seeing that we have a verbatim non-wild-match search. As it happens, this fixes an incorrect test in gdb.ada/homony.exp, where we were inserting a breakpoint on a symbol using the angle-brackets notation, and got 2 locations for that breakpoint... (gdb) b <homonym__get_value> Breakpoint 1 at 0x4029fc: <homonym__get_value>. (2 locations) ... each location being in a different function: (gdb) info break Num Type Disp Enb Address What 1 breakpoint keep y <MULTIPLE> 1.1 y 0x00000000004029fc in homonym.get_value at /[...]/homonym.adb:32 1.2 y 0x0000000000402a3a in homonym.get_value at /[...]/homonym.adb:50 (gdb) x /i 0x00000000004029fc 0x4029fc <homonym__get_value+8>: movl $0x1d,-0x4(%rbp) (gdb) x /i 0x0000000000402a3a 0x402a3a <homonym__get_value__2+8>: movl $0x11,-0x4(%rbp) Since we used angle-brackets, we shouldn't be matching the second one, something this patch fixes. gdb/ChangeLog: * ada-lang.c (standard_lookup): Use ada_lookup_encoded_symbol instead of lookup_symbol_in_language (do_exact_match): New function. (ada_get_symbol_name_matcher): Return do_exact_match when doing a verbatim match. gdb/testsuite/ChangeLog: * gdb.ada/big_packed_array: New testcase. * gdb.ada/homonym.exp: Fix incorrect expected output for "break <homonym__get_value>" test. Tested on x86_64-linux. |
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bfd | ||
binutils | ||
config | ||
contrib | ||
cpu | ||
elfcpp | ||
etc | ||
gas | ||
gdb | ||
gold | ||
gprof | ||
include | ||
intl | ||
ld | ||
libdecnumber | ||
libiberty | ||
opcodes | ||
readline | ||
sim | ||
texinfo | ||
zlib | ||
.cvsignore | ||
.gitattributes | ||
.gitignore | ||
ar-lib | ||
ChangeLog | ||
compile | ||
config-ml.in | ||
config.guess | ||
config.rpath | ||
config.sub | ||
configure | ||
configure.ac | ||
COPYING | ||
COPYING.LIB | ||
COPYING.LIBGLOSS | ||
COPYING.NEWLIB | ||
COPYING3 | ||
COPYING3.LIB | ||
depcomp | ||
djunpack.bat | ||
install-sh | ||
libtool.m4 | ||
ltgcc.m4 | ||
ltmain.sh | ||
ltoptions.m4 | ||
ltsugar.m4 | ||
ltversion.m4 | ||
lt~obsolete.m4 | ||
MAINTAINERS | ||
Makefile.def | ||
Makefile.in | ||
Makefile.tpl | ||
makefile.vms | ||
missing | ||
mkdep | ||
mkinstalldirs | ||
move-if-change | ||
multilib.am | ||
README | ||
README-maintainer-mode | ||
setup.com | ||
src-release.sh | ||
symlink-tree | ||
test-driver | ||
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.