Newer GCCs are triggering false-positive -Wmaybe-uninitialized
warnings around code that uses gdb::optional:
https://sourceware.org/ml/gdb-patches/2017-05/msg00118.html
Using std::optional wouldn't help, it triggers the same warnings:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80635
Initializing the variables to quiet the warning would defeat the
purpose of gdb::optional. Making the optional ctor memset its storage
would be a pessimization. Wrapping gdb::optional's internals with
"#pragma GCC diagnostic push/ignored/pop" doesn't work, we'd have to
wrap uses of gdb::optional instead, which I think would get unwieldy
and ugly as we start using gdb::optional more and more.
The -Wmaybe-uninitialized warning is documented as producing false
positives (unlike -Wuninialized), so until we find a better
workaround, disable -Werror for this warning. You'll still see the
warning when building gdb, but it won't cause a build failure.
Tested by building with gcc 4.8.5, 5.3.1, and gcc trunk (20170428).
gdb/ChangeLog:
2017-05-05 Pedro Alves <palves@redhat.com>
* warning.m4 (build_warnings): Add -Wno-error=maybe-uninitialized.
* configure: Regenerate.
gdb/gdbserver/ChangeLog:
2017-05-05 Pedro Alves <palves@redhat.com>
* configure: Regenerate.
After all the make_cleanup_restore_current_thread fixing, I thought
I'd convert that and its relatives (which are all cleanups) to RAII
classes.
scoped_restore_current_pspace_and_thread was put in a separate file to
avoid a circular dependency.
Tested on x86-64 Fedora 23, native and gdbserver.
gdb/ChangeLog:
2017-05-04 Pedro Alves <palves@redhat.com>
* Makefile.in (SFILES): Add progspace-and-thread.c.
(HFILES_NO_SRCDIR): Add progspace-and-thread.h.
(COMMON_OBS): Add progspace-and-thread.o.
* breakpoint.c: Include "progspace-and-thread.h".
(update_inserted_breakpoint_locations)
(insert_breakpoint_locations, create_longjmp_master_breakpoint):
Use scoped_restore_current_pspace_and_thread.
(create_std_terminate_master_breakpoint): Use
scoped_restore_current_program_space.
(remove_breakpoint): Use scoped_restore_current_pspace_and_thread.
(print_breakpoint_location): Use
scoped_restore_current_program_space.
(bp_loc_is_permanent): Use
scoped_restore_current_pspace_and_thread.
(resolve_sal_pc): Use scoped_restore_current_pspace_and_thread.
(download_tracepoint_locations): Use
scoped_restore_current_pspace_and_thread.
(breakpoint_re_set): Use scoped_restore_current_pspace_and_thread.
* exec.c (exec_close_1): Use scoped_restore_current_program_space.
(enum step_over_calls_kind): Moved from inferior.h.
(class scoped_restore_current_thread): New class.
* gdbthread.h (make_cleanup_restore_current_thread): Delete
declaration.
(scoped_restore_current_thread): New class.
* infcmd.c: Include "common/gdb_optional.h".
(continue_1, proceed_after_attach): Use
scoped_restore_current_thread.
(notice_new_inferior): Use scoped_restore_current_thread.
* inferior.c: Include "progspace-and-thread.h".
(restore_inferior, save_current_inferior): Delete.
(add_inferior_command, clone_inferior_command): Use
scoped_restore_current_pspace_and_thread.
* inferior.h (scoped_restore_current_inferior): New class.
* infrun.c: Include "progspace-and-thread.h" and
"common/gdb_optional.h".
(follow_fork_inferior): Use
scoped_restore_current_pspace_and_thread.
(scoped_restore_exited_inferior): New class.
(handle_vfork_child_exec_or_exit): Use
scoped_restore_exited_inferior,
scoped_restore_current_pspace_and_thread,
scoped_restore_current_thread and scoped_restore.
(fetch_inferior_event): Use scoped_restore_current_thread.
* linespec.c (decode_line_full, decode_line_1): Use
scoped_restore_current_program_space.
* mi/mi-main.c: Include "progspace-and-thread.h".
(exec_continue): Use scoped_restore_current_thread.
(mi_cmd_exec_run): Use scoped_restore_current_pspace_and_thread.
(mi_cmd_trace_frame_collected): Use scoped_restore_current_thread.
* proc-service.c (ps_pglobal_lookup): Use
scoped_restore_current_program_space.
* progspace-and-thread.c: New file.
* progspace-and-thread.h: New file.
* progspace.c (release_program_space, clone_program_space): Use
scoped_restore_current_program_space.
(restore_program_space, save_current_program_space)
(save_current_space_and_thread): Delete.
(switch_to_program_space_and_thread): Moved to
progspace-and-thread.c.
* progspace.h (save_current_program_space)
(save_current_space_and_thread): Delete declarations.
(scoped_restore_current_program_space): New class.
* remote.c (remote_btrace_maybe_reopen): Use
scoped_restore_current_thread.
* symtab.c: Include "progspace-and-thread.h".
(skip_prologue_sal): Use scoped_restore_current_pspace_and_thread.
* thread.c (print_thread_info_1): Use
scoped_restore_current_thread.
(struct current_thread_cleanup): Delete.
(do_restore_current_thread_cleanup)
(restore_current_thread_cleanup_dtor): Rename/convert both to ...
(scoped_restore_current_thread::~scoped_restore_current_thread):
... this new dtor.
(make_cleanup_restore_current_thread): Rename/convert to ...
(scoped_restore_current_thread::scoped_restore_current_thread):
... this new ctor.
(thread_apply_all_command): Use scoped_restore_current_thread.
(thread_apply_command): Use scoped_restore_current_thread.
* tracepoint.c (tdump_command): Use scoped_restore_current_thread.
* varobj.c (value_of_root_1): Use scoped_restore_current_thread.
The unconditional is_stopped call already asserts that the thread exists.
gdb/ChangeLog:
2017-05-04 Pedro Alves <palves@redhat.com>
* thread.c (make_cleanup_restore_current_thread): Move
find_thread_ptid call before the is_stopped call. Assert that the
thread is found. Replace is_stopped call by checking the thread's
state directly. Remove unnecessary NULL-thread check.
This plugs a leak introduced in the previous change to
get_core_register_section, which removed an xfree call that is
actually necessary because the 'section_name' local is static.
From [1] it looks like the reason the variable was made static to
begin with, was just "laziness" to avoid having to think about freeing
it on every function return path:
https://sourceware.org/ml/gdb-patches/2005-03/msg00237.html
The easiest to fix that nowadays is to use a std::string.
I don't see a need to xstrdup the section name in the single-threaded
case though, and also there's more than one place that computes a
multi-threaded section name in the same way. So put the section name
computation in a wrapper class with state.
gdb/ChangeLog:
2017-05-04 Pedro Alves <palves@redhat.com>
* corelow.c (thread_section_name): New class.
(get_core_register_section, get_core_siginfo): Use it.
In corelow.c I stumbled upon an extra semicolon and an xfree of a NULL
pointer. Remove them.
gdb/ChangeLog:
* corelow.c (sniff_core_bfd): Remove extra semicolon.
(get_core_register_section): Remove xfree of NULL pointer.
On some platforms, e.g., arm-eabi-none, we need to make certain that
malloc is linked into the program because the test suite uses function
calls requiring malloc:
(gdb) p foo101("abc")
evaluation of this expression requires the program to have a function "malloc".
gdb/testsuite/ChangeLog
* gdb.cp/oranking.cc (dummy): New function to grab malloc.
(main): Call it.
As Pedro commented on the patch "Change field separator in gdbarch.sh",
this commented out definition is probably not useful and should be
removed. It has been commented out for basically forever, and it
probably serves the same intent as addressable_memory_unit_size.
gdb/ChangeLog:
* gdbarch.sh: Remove commented out definition of
TARGET_CHAR_BIT.
* gdbarch.h: Re-generate.
On commit be628ab814f1c90e185d7482d27aa8a991ab5837, both
common/common.m4 was modified in order to check for the presence of
'termios.h', 'termio.h' and 'sgtty.h'. However, I forgot to
regenerate both gdb/configure and gdb/gdbserver/configure. This
commit does that.
gdb/ChangeLog:
2017-05-03 Sergio Durigan Junior <sergiodj@redhat.com>
* configure: Regenerate.
gdb/gdbserver/ChangeLog:
2017-05-03 Sergio Durigan Junior <sergiodj@redhat.com>
* configure: Regenerate.
Now that we use std::vector, these local variables are not very useful.
They're not much shorter than the expressions they stand for.
gdb/ChangeLog:
* solib-target.c (solib_target_relocate_section_addresses):
Remove num_section_bases, num_bases, segment_bases variables.
Replace the two VEC fields with std::vector.
gdb/ChangeLog:
* solib-target.c: Include <vector>
(struct lm_info_target) <~lm_info_target>: Remove.
<segment_bases, section_bases>: Change type to
std::vector<CORE_ADDR>.
(library_list_start_segment, library_list_start_section,
library_list_end_library,
solib_target_relocate_section_addresses): Adjust.
The fields in the description of the gdbarch interface are separated
using colons. That becomes a problem if we want to use things like
std::vector in it. This patch changes the field separator to use
semicolons instead.
I think there's very little chance we'll ever want to use a semicolon in
one of the fields, but if you think another character would be more
appropriate, let me know.
gdb/ChangeLog:
* gdbarch.sh: Use semi-colon as field separator instead of colon.
* gdbarch.h: Re-generate.
As discussed here: https://sourceware.org/ml/gdb-patches/2017-04/msg00157.html
A gap is not an instruction and it should not pretend to be one.
gdb.Record.instruction_history is now a list of gdb.RecordInstruction and
gdb.RecordGap objects. This allows the user to deal with Gaps in the record
in a more sane way.
The user would always get the instruction_history and function_call_history
objects of the current thread, not the thread for which the gdb.Record object
was created.
The attached testcase fails without this patch and passes with the patch.
This has been on my TODO list for a while. There's a really old bug
about this (PR testsuite/8595), and there was no reason for
environ.exp to be specific for hppa* targets. So this patch removes
this constraint, modernizes the testcase, and cleans up some things.
Most of the tests remained, and some were rewritten (especially the
one that checks if "show environment" works, which is something kind
of hard to do).
As a bonus, I'm adding a separated info-program.exp file containing
all the tests related to "info program" that were present on
environ.exp.
Tested locally, everything still passes.
gdb/testsuite/ChangeLog:
2017-04-28 Sergio Durigan Junior <sergiodj@redhat.com>
PR testsuite/8595
* gdb.base/environ.exp: Make test available in all architectures.
Move bits related to "info program" testing to
gdb.base/info-program.exp. Rewrite tests to use the two new
procedures mentione below.
(test_set_show_env_var) New procedure.
(test_set_show_env_var_equal): Likewise.
* gdb.base/info-program.exp: New file.
With regcache ctor, we can use it to create local object in
get_return_value (), so that the cleanup can be removed.
gdb:
2017-04-28 Yao Qi <yao.qi@linaro.org>
* infcmd.c (get_return_value): Use regcache ctor, and remove
cleanup.
This patch adds a tag dispatch ctor to create read-only regcache from
a write-through regcache, also this patch deletes copy ctor and
assignment operator.
gdb:
2017-04-28 Yao Qi <yao.qi@linaro.org>
Pedro Alves <palves@redhat.com>
* regcache.c (regcache::regcache): New tag dispatch ctor.
(do_cooked_read): Moved above.
(regcache_dup): Use the tag dispatch ctor..
* regcache.h (regcache): Declare ctor, delete copy ctor and
assignment operator, remove friend regcache_dup.
regcache_dup, in fact, is to create a readonly regcache from a
non-readonly regcache. This patch adds an assert that src is not
readonly.
gdb:
2017-04-28 Yao Qi <yao.qi@linaro.org>
* regcache.c (regcache_dup): Assert !src->m_readonly_p and
call method save instead of regcache_cpy.
* regcache.h (struct regcache): Make regcache_dup a friend.
This patch makes lm_info_windows a "real" class. It initializes the field
and replaces XCNEW/xfree with new/delete.
gdb/ChangeLog:
* windows-nat.c (struct lm_info_windows): Initialize field.
(windows_make_so): Allocate lm_info_windows with new.
(windows_free_so): Free lm_info_windows with delete.
This patch makes lm_info_darwin a "real" class. It initializes the
field and replaces XCNEW/xfree with new/delete.
gdb/ChangeLog:
* solib-darwin.c (struct lm_info_darwin): Initialize field.
(darwin_current_sos): Allocate lm_info_darwin with new, remove
cleanup.
(darwin_free_so): Free lm_info_darwin with delete.
This patch makes lm_info_svr4 a "real" class. It initializes fields,
uses bool and replaces XCNEW/xfree with new/delete.
The memcpy in svr4_copy_library_list is replaced by a usage of the
default copy constructor.
gdb/ChangeLog:
* solib-svr4.h (struct lm_info_svr4): Initialize fields.
<l_addr_p>: Change type to bool.
* solib-svr4.c (lm_info_read): Allocate lm_info_svr4 with new.
(svr4_free_so): Free lm_info_svr4 with delete.
(svr4_copy_library_list): Replace memcpy with call to copy
constructor.
(library_list_start_library, svr4_default_sos): Allocate
lm_info_svr4 with new.
This patch makes lm_info_target a "real" class. It adds a destructor,
uses std::string, initializes the fields and replaces XCNEW/xfree with
new/delete.
gdb/ChangeLog:
* solib-target.c (struct lm_info_target): Add destructor,
initialize fields.
<name>: Change type to std::string.
(library_list_start_library): Allocate lm_info_target with new.
(solib_target_free_library_list): Free lm_info_target with
delete.
(solib_target_current_sos): Adapt to std::string.
(solib_target_free_so): Free lm_info_target with delete.
This patches makes lm_info_frv a "real" class. It adds a destructor,
initializes the fields and replaces XCNEW/xfree with new/delete.
gdb/ChangeLog:
* solib-frv.c (struct lm_info_frv): Add destructor, initialize
fields.
(frv_current_sos): Allocate lm_info_frv with new.
(frv_relocate_main_executable): Free lm_info_frv with delete,
allocate with new.
(frv_clear_solib, frv_free_so): Free lm_info_frv with delete.
This patch fixes the indentation of lm_info_frv, so that the real
changes of the following patch are not lost in the reformatting.
gdb/ChangeLog:
* solib-frv.c (struct lm_info_frv): Fix indentation.
This patches makes lm_info_dsbt a "real" class. It introduces a
destructor, initializes the field and replaces XCNEW/xfree with
new/delete.
gdb/ChangeLog:
* solib-dsbt.c (struct lm_info_dsbt): Add destructor, initialize
map field.
(dsbt_current_sos): Allocate lm_info_dsbt with new.
(dsbt_relocate_main_executable): Free lm_info_dsbt with delete
and allocate with new.
(dsbt_clear_solib, dsbt_free_so): Free lm_info_dsbt with delete.
This patch makes lm_info_aix a "real" class. It uses std::string,
initializes fields in-class and replaces XCNEW/xfree with new/delete.
The solib_aix_new_lm_info can be replaced by using the default copy
constructor.
gdb/ChangeLog:
* solib-aix.c (struct lm_info_aix): Initialize fields in-class.
<filename, member_name>: Change type to std::string.
(solib_aix_new_lm_info, solib_aix_xfree_lm_info): Remove.
(library_list_start_library): Allocate lm_info_aix with new.
(solib_aix_free_library_list, solib_aix_free_so): Free with delete.
(solib_aix_current_sos): Adapt to std::string, copy lm_info_aix
with copy constructor.
The lm_info structure is used to store target specific information about
mapped libraries. It is currently defined as an opaque type in solist.h
and a pointer to it is included in solist, the target-agnostic object
representing a loaded shared library. Multiple targets define their own
implementation of lm_info.
In anticipation of using C++ stuff (e.g. vector) in the lm_info objects,
we first need to avoid different definitions of classes with the same
name (which violates the one definition rule). This patch does it by
having a base class (lm_info_base) from which all the specific lm_info
derive. Each implementation is renamed to something that makes sense
(e.g. lm_info_aix for AIX). The next logical step would probably be to
derive directly from so_list, it's not really obvious, so I'll keep that
for another day.
One special case is the Neutrino (nto) support. It uses SVR4-style
libraries, but overrides some methods. To do that, it needed to have
its own copy of SVR4's lm_info structure in nto-tdep.c, because it was
just not possible to put it in solib-svr4.h and include that file. Over
time, that copy got out of sync, which is still the case today. I can
only assume that the lm_addr function in nto-tdep.c is broken right now.
The first field of the old lm_info was a pointer (gdb_byte *), whereas
in the new lm_info it's an address in the inferior (CORE_ADDR). Trying
to use that field today probably results in a crash. With this
refactor, it's now possible to put lm_info_svr4 in solib-svr4.h and just
include it. I have adapted the code in nto-tdep.c to that it builds,
but it's probably not correct. Since I don't have the knowledge nor
setup to try this on Neutrino, somebody else would have to fix it. But
I am confident that I am not making things worse than they already are.
gdb/ChangeLog:
* solist.h (struct lm_info): Remove.
(struct lm_info_base): New class.
(struct so_list) <lm_info>: Change type to lm_info_base *.
* nto-tdep.c (struct lm_info): Remove.
(lm_addr): Adjust.
* solib-aix.c (struct lm_info): Rename to ...
(struct lm_info_aix): ... this. Extend lm_info_base.
(lm_info_p): Rename to ...
(lm_info_aix_p): ... this, and adjust.
(solib_aix_new_lm_info, solib_aix_xfree_lm_info,
solib_aix_parse_libraries, library_list_start_library,
solib_aix_free_library_list, solib_aix_parse_libraries,
solib_aix_get_library_list,
solib_aix_relocate_section_addresses, solib_aix_free_so,
solib_aix_get_section_offsets,
solib_aix_solib_create_inferior_hook, solib_aix_current_sos):
Adjust.
(struct solib_aix_inferior_data) <library_list>: Adjust.
* solib-darwin.c (struct lm_info): Rename to ...
(struct lm_info_darwin): ... this. Extend lm_info_base.
(darwin_current_sos, darwin_relocate_section_addresses): Adjust.
* solib-dsbt.c (struct lm_info): Rename to ...
(struct lm_info_dsbt): ... this. Extend lm_info_base.
(struct dsbt_info) <main_executable_lm_info): Adjust.
(dsbt_current_sos, dsbt_relocate_main_executable, dsbt_free_so,
dsbt_relocate_section_addresses): Adjust.
* solib-frv.c (struct lm_info): Rename to ...
(struct lm_info_frv): ... this. Extend lm_info_base.
(main_executable_lm_info): Adjust.
(frv_current_sos, frv_relocate_main_executable, frv_free_so,
frv_relocate_section_addresses, frv_fdpic_find_global_pointer,
find_canonical_descriptor_in_load_object,
frv_fdpic_find_canonical_descriptor): Adjust.
* solib-svr4.c (struct lm_info): Move to solib-svr4.h, renamed
to lm_info_svr4.
(lm_info_read, lm_addr_check, svr4_keep_data_in_core,
svr4_clear_so, svr4_copy_library_list,
library_list_start_library, svr4_default_sos, svr4_read_so_list,
svr4_current_sos, svr4_fetch_objfile_link_map,
solist_update_incremental): Adjust.
* solib-svr4.h (struct lm_info_svr4): Move here from
solib-svr4.c.
* solib-target.c (struct lm_info): Rename to ...
(struct lm_info_target): ... this. Extend lm_info_base.
(lm_info_p): Rename to ...
(lm_info_target_p): ... this.
(solib_target_parse_libraries, library_list_start_segment,
library_list_start_section, library_list_start_library,
library_list_end_library, solib_target_free_library_list,
solib_target_current_sos, solib_target_free_so,
solib_target_relocate_section_addresses): Adjust.
* windows-nat.c (struct lm_info): Rename to ...
(struct lm_info_windows): ... this. Extend lm_info_base.
(windows_make_so, handle_load_dll, handle_unload_dll,
windows_xfer_shared_libraries): Adjust.
Darwin's lm_info structure is used a little bit differently than the
other solib implementations. The other implementations first allocate
an so_list object, then instanciate their specific lm_info structure,
and assign it to so_list::lm_info.
The Darwin implementation allocates both at the same time
(darwin_so_list). This patch changes it to be like the others, so that
we'll be able to do some generalizations later.
gdb/ChangeLog:
* solib-darwin.c (struct darwin_so_list): Remove.
(darwin_current_sos): Allocate an so_list object instead of a
darwin_so_list, separately allocate an lm_info object.
(darwin_free_so): Free lm_info.
One line was using printf_filtered instead of fprintf_filtered
to the requested file.
gdb/ChangeLog:
* mips-tdep.c (print_gp_register_row): Replace printf_filtered
with fprintf_filtered.
This patch adds ctor and dtor to regcache.
gdb:
2017-04-28 Yao Qi <yao.qi@linaro.org>
* regcache.c (regcache::regcache): New function.
(regcache::~regcache): New function.
(regcache_xmalloc_1): Remove.
(regcache_xmalloc): Call new regcache.
(regcache_xfree): Call delete regcache.
(get_thread_arch_aspace_regcache): Call new regcache.
RAJESH reported that GDB gets "Couldn't write debug register: No such
process." on mips64 when GDB attaches to a multi threaded application.
Looks GDB nows PTRACE_GET_WATCH_REGS for inferior_ptid but
PTRACE_SET_WATCH_REGS for lwp->ptid, they may be different.
gdb:
2017-04-28 Yao Qi <yao.qi@linaro.org>
* mips-linux-nat.c (mips_linux_new_thread): Get lwpid from
lwp_info instead of getting from inferior_ptid.
The following patch fixes several outstanding overload resolution problems
with rvalue references and cv qualifiers in the test suite. The tests for
these problems typically passed with one compiler version and failed with
another. This behavior occurs because of the ordering of the overloaded
functions in the debug info. So the first best match "won out" over the
a subsequent better match.
One of the bugs addressed by this patch is the failure of rank_one_type to
account for type equality of two overloads based on CV qualifiers. This was
leading directly to problems evaluating rvalue reference overload quality,
but it is also highlighted in gdb.cp/oranking.exp, where two test KFAIL as
a result of this shortcoming.
I found the overload resolution code committed with the rvalue reference
patch (f9aeb8d49) needlessly over-complicated, and I have greatly simplified
it. This fixes some KFAILing tests in gdb.exp/rvalue-ref-overload.exp.
gdb/ChangeLog
* gdbtypes.c (LVALUE_REFERENCE_TO_RVALUE_BINDING_BADNESS)
DIFFERENT_REFERENCE_TYPE_BADNESS): Remove.
(CV_CONVERSION_BADNESS): Define.
(rank_one_type): Remove overly restrictive rvalue reference
rank checks.
Add cv-qualifier checks and subranks for type equality.
* gdbtypes.h (REFERENCE_CONVERSION_RVALUE,
REFERENCE_CONVERSION_CONST_LVALUE, CV_CONVERSION_BADNESS,
CV_CONVERSION_CONST, CV_CONVERSION_VOLATILE): Declare.
gdb/testsuite/ChangeLog
* gdb.cp/oranking.cc (test15): New function.
(main): Call test15 and declare additional variables for testing.
* gdb.cp/oranking.exp: Remove kfail status for "p foo4(&a)" and
"p foo101('abc')" tests.
* gdb.cp/rvalue-ref-overloads.exp: Remove kfail status for
"lvalue reference overload" test.
* gdb.cp/rvalue-ref-params.exp: Remove kfail status for
"print value of f1 on Child&& in f2" test.
The test py-inferior.exp fails when using a debug build of Python 3.6. I don't
see it failing with my system's default Python, but it might be related to the
different memory allocation scheme used when doing a build with pydebug.
The issue is that we are missing a Py_INCREF in
inferior_to_inferior_object. The PyObject_New function initializes the
object with a refcount of 1. If we assume that this refcount
corresponds to the reference we are returning, then we are missing an
incref for the reference in the inferior data.
The counterpart for the incref that corresponds to the reference in the
inferior data is in py_free_inferior, in the form the gdbpy_ref instance.
Here's how I can get it to crash (with some debug output):
$ ./gdb -nx -ex "set debug python 1"
(gdb) add-inferior
Added inferior 2
(gdb) python infs = gdb.inferiors()
Creating Python Inferior object inf = 1
Creating Python Inferior object inf = 2
(gdb) remove-inferiors 2
py_free_inferior inf = 2
infpy_dealloc inf = <unknown>
(gdb) python infs = None
Fatal Python error: Objects/tupleobject.c:243 object at 0x7f9cf1a568d8 has negative ref count -1
Current thread 0x00007f9cf1b68780 (most recent call first):
File "<string>", line 1 in <module>
[1] 408 abort (core dumped) ./gdb -nx -ex "set debug python 1"
After having created the inferiors object, their refcount is 1 (which
comes from PyObject_New), but it should be two. The gdb inferior object
has a reference and the "infs" list has a reference.
When invoking remove-inferiors, py_free_inferior gets called. It does
the decref that corresponds to the reference that the gdb inferior
object kept. At this moment, the refcount drops to 0 and the object
gets deallocated, even though the "infs" list still has a reference.
When we set "infs" to None, Python tries to decref the already zero
refcount and the assert triggers.
With this patch, it looks better:
(gdb) add-inferior
Added inferior 2
(gdb) python infs = gdb.inferiors()
Creating Python Inferior object inf = 1
Creating Python Inferior object inf = 2
(gdb) remove-inferiors 2
py_free_inferior inf = 2
(gdb) python infs = None
infpy_dealloc inf = <unknown>
gdb/ChangeLog:
* python/py-inferior.c (inferior_to_inferior_object): Increment reference
count when creating the object.
Fix handling of XCOFF function auxiliary entries, in particular when
the xlc -qfuncsect or gcc -ffunction-sections compiler option is used
in AIX. Also handle C_WEAKEXT storage class.
gdb/
2016-10-21 Sangamesh Mallayya <sangamesh.swamy@in.ibm.com>
Ulrich Weigand <uweigand@de.ibm.com>
* xcoffread.c (read_xcoff_symtab): Read correct function auxiliary
entry if xlc -qfuncsect or gcc -ffunction-sections compiler option
is used in AIX.
(read_xcoff_symtab): Handle C_WEAKEXT storage class.
(process_xcoff_symbol): Likewise.
(scan_xcoff_symtab): Likewise.
Signed-off-by: Ulrich Weigand <ulrich.weigand@de.ibm.com>
Recently a feature called "return address signing" has been added to GCC to
prevent stack smash stack on AArch64. For details please refer:
https://gcc.gnu.org/ml/gcc-patches/2017-01/msg00376.html
GDB needs to be aware of this feature so it can restore the original return
address which is critical for unwinding.
On compiler side, whenever return address, i.e. LR register, is mangled or
restored by hardware instruction, compiler is expected to generate a
DW_CFA_AARCH64_negate_ra_state to toggle return address signing status.
DW_CFA_AARCH64_negate_ra_state is using the same CFI number and
therefore need to be multiplexed with DW_CFA_GNU_window_save which was designed
for SPARC.
A new gdbarch method "execute_dwarf_cfa_vendor_op" is introduced by this patch.
It's parameters has been restricted to those only needed by SPARC and AArch64
for multiplexing DW_CFA_GNU_window_save which is a CFI operation takes none
operand. Should any further DWARF CFI operation want to be multiplexed in the
future, the parameter list can be extended. Below is the current function
prototype.
typedef int (gdbarch_execute_dwarf_cfa_vendor_op_ftype)
(struct gdbarch *gdbarch, gdb_byte op, struct dwarf2_frame_state *fs);
DW_CFA_GNU_window_save support for SPARC is migrated to this new gdbarch
method by this patch.
gdb/
* gdbarch.sh: New gdbarch method execute_dwarf_cfa_vendor_op.
* gdbarch.c: Regenerated.
* gdbarch.h: Regenerated.
* dwarf2-frame.c (dwarf2_frame_state_alloc_regs): Made the
visibility external.
(execute_cfa_program): Call execute_dwarf_cfa_vendor_op for CFI
between DW_CFA_lo_user and DW_CFA_high_user inclusive.
(enum cfa_how_kind): Move to ...
(struct dwarf2_frame_state_reg_info): Likewise.
(struct dwarf2_frame_state): Likewise.
* dwarf2-frame.h: ... here.
(dwarf2_frame_state_alloc_regs): New declaration.
* sparc-tdep.c (sparc_execute_dwarf_cfa_vendor_op): New function.
(sparc32_gdbarch_init): Register execute_dwarf_cfa_vendor_op hook.
