Consider the following declarations:
type Signed_Small is new Integer range - (2 ** 5) .. (2 ** 5 - 1);
type Signed_Simple_Array is array (1 .. 4) of Signed_Small;
pragma Pack (Signed_Simple_Array);
SSA : Signed_Simple_Array := (-1, 2, -3, 4);
GDB currently print its value incorrectly for the elements that
are negative:
(gdb) print ssa
$1 = (65535, 2, 1048573, 4)
(gdb) print ssa(1)
$2 = 65535
(gdb) print ssa(2)
$3 = 2
(gdb) print ssa(3)
$4 = 1048573
(gdb) print ssa(4)
$5 = 4
What happens is that the sign-extension is not working because
we're trying to do left shift with a negative count. In
ada_value_primitive_packed_val, we have a loop which populates
the extra bits of the target (unpacked) value, after extraction
of the data from the original (packed) value:
while (ntarg > 0)
{
accum |= sign << accumSize;
unpacked[targ] = accum & ~(~0L << HOST_CHAR_BIT);
!!! -> accumSize -= HOST_CHAR_BIT;
accum >>= HOST_CHAR_BIT;
ntarg -= 1;
targ += delta;
}
At each iteration, accumSize gets decremented by HOST_CHAR_BIT,
which can easily cause it to become negative, particularly on
little endian targets, where accumSize is at most HOST_CHAR_BIT - 1.
This causes us to perform a left-shift operation with a negative
accumSize at the next loop iteration, which is undefined, and
acutally does not produce the effect we wanted (value left untouched)
when the code is compiled with GCC.
This patch fixes the issue by simply setting accumSize to zero
if negative.
gdb/ChangeLog:
* ada-lang.c (ada_value_primitive_packed_val): Make sure
accumSize is never negative.
gdb/testsuite/ChangeLog:
* gdb.ada/pckd_neg: New testcase.
This patch adds -mshared option to x86 ELF assembler. By default,
assembler will optimize out non-PLT relocations against defined non-weak
global branch targets with default visibility. The -mshared option tells
the assembler to generate code which may go into a shared library
where all non-weak global branch targets with default visibility can
be preempted. The resulting code is slightly bigger. This option
only affects the handling of branch instructions.
This Linux kernel patch is needed to create a working x86 Linux kernel if
it hasn't been applied:
diff --git a/arch/x86/kernel/head_64.S b/arch/x86/kernel/head_64.S
index ae6588b..b91a00c 100644
--- a/arch/x86/kernel/head_64.S
+++ b/arch/x86/kernel/head_64.S
@@ -339,8 +339,8 @@ early_idt_handlers:
i = i + 1
.endr
-/* This is global to keep gas from relaxing the jumps */
-ENTRY(early_idt_handler)
+/* This is weak to keep gas from relaxing the jumps */
+WEAK(early_idt_handler)
cld
cmpl $2,(%rsp) # X86_TRAP_NMI
--
gas/
* config/tc-i386.c (shared): New.
(OPTION_MSHARED): Likewise.
(elf_symbol_resolved_in_segment_p): Add relocation argument.
Check PLT relocations and shared.
(md_estimate_size_before_relax): Pass fragP->fr_var to
elf_symbol_resolved_in_segment_p.
(md_longopts): Add -mshared.
(md_show_usage): Likewise.
(md_parse_option): Handle OPTION_MSHARED.
* doc/c-i386.texi: Document -mshared.
gas/testsuite/
* gas/i386/i386.exp: Don't run pcrel for ELF targets. Run
pcrel-elf, relax-4 and x86-64-relax-3 for ELF targets.
* gas/i386/pcrel-elf.d: New file.
* gas/i386/relax-4.d: Likewise.
* gas/i386/x86-64-relax-3.d: Likewise.
* gas/i386/relax-3.d: Pass -mshared to assembler. Updated.
* gas/i386/x86-64-relax-2.d: Likewise.
* gas/i386/relax-3.s: Add test for PLT relocation.
PR binutils/18374
bin * dwarf.h (struct dwarf_section): Add reloc_info and num_relocs
fields.
(struct dwarf_section_display): Change bitfield to boolean.
(reloc_at): Add prototype.
* dwarf.c (display_loc_list): Ignore list terminators if there are
relocs against them.
(display_debug_loc): Issue a warning if there are relocs against
the .debug_loc section.
(display_displays): Initialise reloc_info and num_relocs fields.
* objdump.c (load_specific_debug_section): Initialise reloc_info
and num_relocs fields.
(reloc_at): New function.
* readelf.c (is_32bit_abs_reloc): Add IA64's R_IA64_DIS32LSB
reloc.
(reloc_at): New function.
(apply_relocations): Add relocs_return and num_relocs_return
parameters. Fill them in with the loaded relocs if non-NULL.
(dump_section_as_bytes): Update call to apply_relocations.
(load_specific_debug_section): Initialise reloc_info and
num_relocs fields.
tests * binutils-all/pr18374.s: New test file.
* binutils-all/readelf.exp: Assemble and run the new test.
* binutils-all/readelf.pr18374: Expected output from readelf.
Remove the wait instructions for server processors, since they were never
implemented. Also add the extra operands added to the tlbie and slbia
instructions with ISA 2.06 and ISA 2.05 respectively.
binutils/
* MAINTAINERS: Add myself as PPC maintainer.
opcodes/
* ppc-opc.c (IH) New define.
(powerpc_opcodes) <wait>: Do not enable for POWER7.
<tlbie>: Add RS operand for POWER7.
<slbia>: Add IH operand for POWER6.
gas/testsuite/
* gas/ppc/power4.d: Add a slbia test.
* gas/ppc/power4.s: Likewise.
* gas/ppc/power6.d: Add slbia and tlbie tests.
* gas/ppc/power6.s: Likewise.
* gas/ppc/power7.d: Remove wait tests. Add a tlbie test.
* gas/ppc/power7.s: Likewise.
In a SHF_COMPRESSED compressed section, the raw compressed data should
begin immediately after the compression header. This patch removes the
extra zlib header from the SHF_COMPRESSED section.
bfd/
* bfd.c (bfd_update_compression_header): Also write the zlib
header if the SHF_COMPRESSED bit cleared..
(bfd_check_compression_header): Return the uncompressed size.
* compress.c (decompress_contents): Don't skip the zlib header.
(bfd_compress_section_contents): Properly handle ELFCOMPRESS_ZLIB,
which doesn't have the zlib header.
(bfd_init_section_decompress_status): Likewise.
(bfd_get_full_section_contents): Updated.
(bfd_is_section_compressed): Likewise.
(bfd_is_section_compressed_with_header): Return the uncompressed
size.
* elf.c (_bfd_elf_make_section_from_shdr): Updated.
* bfd-in2.h: Regenerated.
binutils/
* readelf.c (uncompress_section_contents): Add a parameter for
uncompressed size. Don't check the zlib header.
(load_specific_debug_section): Updated.
binutils/testsuite/
* binutils-all/compress.exp: Replace "$OBJDUMP -s -j .debug_info"
with "$OBJDUMP -W".
* binutils-all/libdw2-compressedgabi.out: Updated.
gas/
2015-05-14 H.J. Lu <hongjiu.lu@intel.com>
* write.c (compress_debug): Don't write the zlib header, which
is handled by bfd_update_compression_header.
Fix build errors introduced by
https://sourceware.org/ml/gdb-patches/2015-05/msg00281.html, which
didn't account for the change of the name of the struct process_info
field 'private' to 'priv' made in
https://sourceware.org/ml/gdb-patches/2015-02/msg00829.html.
gdb/gdbserver/ChangeLog:
* linux-aarch64-low.c (aarch64_linux_new_fork): Change reference
to process_info.private to process_info.priv.
* linux-arm-low.c (arm_new_fork): Likewise.
* linux-mips-low.c (mips_linux_new_fork): Likewise.
The following patch...
| proc-service, extern "C"
|
| libthread_db.so calls symbols in the client (GDB), through the
| proc-service interface. These routines must have extern "C" linkage
| so their symbol names are not mangled when GDB is built as a C++
| program. On the GDBserver side, we were missing fallback declarations for
| all these symbols.
|
| gdb/ChangeLog:
|
| * gdb_proc_service.h: Wrap with EXTERN_C_PUSH/EXTERN_C_POP.
|
| gdb/gdbserver/ChangeLog:
| 2015-02-27 Pedro Alves <palves@redhat.com>
|
| * gdb_proc_service.h: Wrap with EXTERN_C_PUSH/EXTERN_C_POP.
| [!HAVE_PROC_SERVICE_H] (struct ps_prochandle): Forward declare.
| [!HAVE_PROC_SERVICE_H] (ps_pdread, ps_pdwrite, ps_ptread)
| ps_ptwrite, ps_lgetregs, ps_lsetregs, ps_lgetfpregs)
| (ps_lsetfpregs, ps_getpid)
| (ps_get_thread_area, ps_pglobal_lookup, ps_pstop, ps_pcontinue)
| (ps_lstop, ps_lcontinue, ps_lgetxregsize, ps_lgetxregs)
| (ps_lsetxregs, ps_plog): Declare.
... added a number of declarations which do not compile when cross-
compiling GDBserver on arm-android. The problem comes from type
prfpregset_t not being declared:
/[...]/gdbserver/gdb_proc_service.h:98:47:
error: unknown type name 'prfpregset_t'
After searching through the includes of the install we have,
I could not find that type being declared anywhere. So I did
the same as for prgregset_t, and created the typedef if the
type isn't declared.
gdb/gdbserver/ChangeLog:
* configure.ac: Add prfpregset_t BFD_HAVE_SYS_PROCFS_TYPE check.
* configure, config.in: Regenerate.
* gdb_proc_service.h [HAVE_PRFPREGSET_T] (prfpregset_t):
Declare typedef.
The function tui_dispatch_ctrl_char() has an old workaround (from 1999)
for buggy terminals and/or ncurses library that don't return page
up/down keys as single characters. Because the workaround is so old, I
think the bug it is targetting is no longer relevant anymore.
But more importantly, the workaround is itself buggy: it 1) performs a
blocking call to wgetch() and 2) if the key returned by wgetch() does
not make up a relevant key sequence it throws away the input instead of
pushing it back via ungetch(). And indeed the workaround breaks Alt-key
sequences under TERM=xterm because of bug #2.
So this patch removes the buggy workaround and tidies up the function
accordingly.
I personally tested this change on a recent xterm (with TERM=xterm) in
Fedora 20 and had no problems with having ncurses properly interpret
page up/down keys. And Alt-key sequences now work when TERM=xterm too.
gdb/ChangeLog:
* tui/tui-command.c: Remove include of <ctype.h>.
(tui_dispatch_ctrl_char): Remove workaround for xterm terminals.
elf_xtensa_gc_sweep_hook doesn't correctly unreference symbols that were
made local, that results in link failure with the following message:
BFD (GNU Binutils) 2.24 internal error, aborting at elf32-xtensa.c line
3372 in elf_xtensa_finish_dynamic_sections
elf_xtensa_gc_sweep_hook determines symbol reference type (PLT or GOT) by
relocation type. Relocation types are not changed when symbol becomes
local, but its PLT references are added to GOT references and
plt.refcount is set to 0. Such symbol cannot be unreferences in the
elf_xtensa_gc_sweep_hook and its extra references make calculated GOT
relocations section size not match number of GOT relocations.
Fix it by treating PLT reference as GOT reference when plt.refcount is
not positive.
2015-05-14 Max Filippov <jcmvbkbc@gmail.com>
bfd/
* elf32-xtensa.c (elf_xtensa_gc_sweep_hook): Treat PLT reference
as GOT reference when plt.refcount is not positive.
regcache_cpy_no_passthrough is no longer used for a standalone call.
gdb/ChangeLog
2015-05-13 Jan Kratochvil <jan.kratochvil@redhat.com>
* regcache.c (regcache_cpy_no_passthrough): New declaration.
(regcache_cpy_no_passthrough): Make it static, add function comment.
* regcache.h (regcache_dup, regcache_cpy): Reduce/update their comment.
(regcache_cpy_no_passthrough): Remove declaration.
Now stop_registers are no longer used and it can be removed.
I am not much sure what 'proceed_to_finish' really means now so I make a wild
guess while updating comments about it.
gdb/ChangeLog
2015-05-13 Jan Kratochvil <jan.kratochvil@redhat.com>
* gdbthread.h (struct thread_control_state): Update comment for
proceed_to_finish.
* infcall.c (run_inferior_call): Update comment about
proceed_to_finish.
* infcmd.c (get_return_value): Update comment about stop_registers.
(finish_forward): Update comment about proceed_to_finish.
* infrun.c (stop_registers): Remove.
(clear_proceed_status, normal_stop): Remove stop_registers handling.
* infrun.h (stop_registers): Remove.
With dummy_frame destructors GDB no longer has to use global stop_registers.
dummy_frame's registers can be now stored associated with their specific
dummy_frame.
gdb/ChangeLog
2015-05-13 Jan Kratochvil <jan.kratochvil@redhat.com>
* infcall.c (struct dummy_frame_context_saver)
(dummy_frame_context_saver_data_free, dummy_frame_context_saver_dtor)
(dummy_frame_context_saver_drop, dummy_frame_context_saver_cleanup)
(dummy_frame_context_saver_get_regs, dummy_frame_context_saver_setup):
New.
(call_function_by_hand_dummy): Move discard_cleanups of
inf_status_cleanup before dummy_frame_push. Call
dummy_frame_context_saver_setup and prepare context_saver_cleanup.
Use dummy_frame_context_saver_get_regs instead of stop_registers.
* infcall.h (struct dummy_frame_context_saver)
(dummy_frame_context_saver_drop, dummy_frame_context_saver_cleanup)
(dummy_frame_context_saver_get_regs, dummy_frame_context_saver_setup):
New declarations.
* infcmd.c: Include infcall.h.
(get_return_value): Add parameter ctx_saver, use it instead of
stop_registers.
(print_return_value): Add parameter ctx_saver, pass it.
(struct finish_command_continuation_args): Add field ctx_saver.
(finish_command_continuation): Update print_return_value caller.
(finish_command_continuation_free_arg): Free also ctx_saver.
(finish_forward): Call dummy_frame_context_saver_setup.
* inferior.h (struct dummy_frame_context_saver): New declaration.
(get_return_value): Add parameter ctx_saver.
* python/py-finishbreakpoint.c (bpfinishpy_pre_stop_hook): Update
get_return_value caller.
Later patch needs two independent destructors for the same dummy_frame.
Therefore the registrar has been extended to an arbitrary number of
destructors.
gdb/ChangeLog
2015-05-13 Jan Kratochvil <jan.kratochvil@redhat.com>
* dummy-frame.c (struct dummy_frame_dtor_list): New.
(struct dummy_frame): Replace dtor and dtor_data by dtor_list.
(remove_dummy_frame): Process dtor_list.
(pop_dummy_frame): Process dtor_list.
(register_dummy_frame_dtor): Maintain dtor_list.
(find_dummy_frame_dtor): Handle dtor_list.
* dummy-frame.h (register_dummy_frame_dtor, find_dummy_frame_dtor):
Update comments.
There was now a leak-like bug that if dummy_frame "disappeared" by
remove_dummy_frame then its destructor was not called. For example in the case
of 'compile code' dummy frames the injected objfile would never get freed after
some inferior longjmp out of the injected code.
gdb/ChangeLog
2015-05-13 Jan Kratochvil <jan.kratochvil@redhat.com>
* compile/compile-object-run.c (do_module_cleanup): Add parameter
registers_valid.
(compile_object_run): Update do_module_cleanup caller.
* dummy-frame.c: Include infcall.h.
(struct dummy_frame): Update dtor comment.
(remove_dummy_frame): Call dtor.
(pop_dummy_frame): Update dtor caller.
* dummy-frame.h (dummy_frame_dtor_ftype): Add parameter
registers_valid.
As this change was ported to GDB 7.9.1, the NEWS entry is moved to
a newly-created "Changes in GDB 7.9.1" section, matching the NEWS
file which is going to be distributed with the GDB 7.9.1 release.
gdb/ChangeLog:
* NEWS: Create "Changes in GDB 7.9.1" section. Move news about
Xmethods now being able to specify a result type to that new
section.
Extra condition 'abs (addr - trampaddr) < J_RANGE / 2' for trampoline
selection results in regressions: when relaxable jump is little longer
than J_RANGE so that single trampoline makes two new jumps, one longer
than J_RANGE / 2 and one shorter, correct trampoline cannot be found.
Drop that condition.
2015-05-13 Max Filippov <jcmvbkbc@gmail.com>
gas/
* config/tc-xtensa.c (xtensa_relax_frag): Allow trampoline to be
closer than J_RANGE / 2 to jump frag.
gas/testsuite/
* gas/xtensa/trampoline.s: Add regression testcase.
The control variable win_resized must be cleared before responding to
it.
Otherwise there is a small window where another SIGWINCH might occur in
between the handling of an earlier SIGWINCH and the clearing of
win_resized, at which point win_resized would be set (again) by the
signal handler. Shortly thereafter we would clear win_resized even
though we only handled the earlier SIGWINCH but not the latest one.
This chain of events is all avoided if we clear win_resized first.
gdb/ChangeLog:
* tui/tui-win.c (tui_async_resize_screen): Clear win_resized
first before resizing the window.
* tui.c (tui_enable): Likewise.
Both dummy_frame_dtor_ftype and call_function_by_hand_dummy_dtor_ftype
represent the same type, there was some mistake/duplication during check-in.
gdb/ChangeLog
2015-05-08 Jan Kratochvil <jan.kratochvil@redhat.com>
* dummy-frame.c (struct dummy_frame): Use proper typedef for dtor.
* dummy-frame.h (dummy_frame_dtor_ftype): Add its comment.
* infcall.c (call_function_by_hand_dummy): Use proper typedef for
dummy_dtor parameter.
* infcall.h: Include dummy-frame.h.
(call_function_by_hand_dummy_dtor_ftype): Remove.
(call_function_by_hand_dummy): Use proper typedef for dummy_dtor
parameter.
This patch is a comprehensive fix for PR 17820 which reports that
using "set history size unlimited" inside one's gdbinit file doesn't
really work.
There are three small changes in this patch. The most important change
this patch makes is to decode the argument of the "size" subcommand
using add_setshow_zuinteger_unlimited_cmd() instead of using
add_setshow_uinteger_cmd(). The new decoder takes an int * and maps
unlimited to -1 whereas the old decoder takes an unsigned int * and maps
unlimited to UINT_MAX. Using the new decoder simplifies our handling of
unlimited and makes it easier to interface with readline which itself
expects a signed-int history size.
The second change is the factoring of the [stifle|unstifle]_history logic
into a common function which is now used by both init_history() and
set_history_size_command(). This is technically the change that fixes
the PR itself.
Thirdly, this patch initializes history_size_setshow_var to -2 to mean
that the variable has not been set yet. Now init_history() tests for -2
instead of 0 to determine whether to give the variable a default value.
This means that having "set history size 0" in one's gdbinit file will
actually keep the history size at 0 and not reset it to 256.
gdb/ChangeLog:
PR gdb/17820
* top.c (history_size_setshow_var): Change type to signed.
Initialize to -2. Update documentation.
(set_readline_history_size): Define.
(set_history_size_command): Use it. Remove logic for handling
out-of-range sizes.
(init_history): Use set_readline_history_size(). Test for a
value of -2 instead of 0 when determining whether to set a
default history size.
(init_main): Decode the argument of the "size" command as a
zuinteger_unlimited.
gdb/testsuite/ChangeLog:
PR gdb/17820
* gdb.base/gdbinit-history.exp: New test.
* gdb.base/gdbinit-history/unlimited/.gdbinit: New file.
* gdb.base/gdbinit-history/zero/.gdbinit: New file.
Commit dd7e64d45b may optimize out
i386/x86-64 JUMP_SLOT relocation. If there is no JUMP_SLOT relocation
left, we don't need to the first .plt entry. This patch allocates
space for the first .plt entry only if we also reserve space for a PLT
slot for JUMP_SLOT relocation.
bfd/
* elf32-i386.c (elf_i386_allocate_dynrelocs): Allocate space
for the first .plt entry only if needed.
* elf64-x86-64.c (elf_x86_64_allocate_dynrelocs): Likewise.
ld/testsuite/
* ld-i386/i386.exp: Run pltgot-1 for Linux targets.
* ld-x86-64/x86-64.exp: Likewise.
* ld-i386/pltgot-1.d: New file.
* ld-i386/pltgot-1.s: Likewise.
* ld-x86-64/pltgot-1.d: Likewise.
* ld-x86-64/pltgot-1.s: Likewise.
This patch contains the accumulated documentation changes for the
rest of the extended-remote follow fork patchset.
gdb/ChangeLog:
* NEWS: Announce fork support in the RSP and support
for fork debugging in extended mode.
gdb/doc/ChangeLog:
* gdb.texinfo (Forks): Note that fork debugging is
supported in extended mode.
(Remote Configuration): Add fork event features to table
of packet settings.
(Stop Reply Packets): Add fork events to list of stop reasons.
(General Query Packets): Add fork events to tables of
'gdbfeatures' and 'stub features' supported in the qSupported
packet, as well as to the list containing stub feature
details.
This patch implements catchpoints for fork events on extended-remote
Linux targets.
Implementation appeared to be straightforward, requiring four new functions
in remote.c to implement insert/remove of fork/vfork catchpoints. These
functions are essentially stubs that just return 0 ('success') if the
required features are enabled. If the fork events are being reported, then
catchpoints are set and hit.
However, there are some extra issues that arise with catchpoints.
1) Thread creation reporting -- fork catchpoints are hit before the
follow_fork has been completed. When stopped at a fork catchpoint
in the native implementation, the new process is not 'reported'
until after the follow is done. It doesn't show up in the inferiors
list or the threads list. However, in the gdbserver case, an
'info threads' while stopped at a fork catchpoint will retrieve the
new thread info from the target and add it to GDB's data structures,
prior to the follow operations. Because of this premature report,
things on the GDB side eventually get very confused.
So in remote.c:remote_update_thread_list, we check to see if there
are any pending fork parent threads. If there are we remove the
related fork child thread from the thread list sent by the target.
2) Kill process before fork is followed -- on the native side in
linux-nat.c:linux_nat_kill, there is some code to handle the case where
a fork has occurred but follow_fork hasn't been called yet. It does
this by using the last status to determine if a follow is pending, and
if it is, to kill the child task. The use of last_status is fragile
in situations like non-stop mode where other events may have occurred
after the fork event. This patch identifies a fork parent
in remote.c:extended_remote_kill in a way similar to that used in
thread creation reporting above. If one is found, it kills the new
child as well.
Tested on x64 Ubuntu Lucid, native, remote, extended-remote. Tested the
case of killing the forking process before the fork has been followed
manually.
gdb/ChangeLog:
* remote.c (remote_insert_fork_catchpoint): New function.
(remote_remove_fork_catchpoint): New function.
(remote_insert_vfork_catchpoint): New function.
(remote_remove_vfork_catchpoint): New function.
(pending_fork_parent_callback): New function.
(remove_new_fork_child): New function.
(remote_update_thread_list): Call remote_notif_get_pending_events
and remove_new_fork_child.
(extended_remote_kill): Kill fork child when killing the
parent before follow_fork completes.
(init_extended_remote_ops): Initialize target vector with
new fork catchpoint functions.
This patch implements follow-fork for vfork on extended-remote Linux targets.
The implementation follows the native implementation as much as possible.
Most of the work is done on the GDB side in the existing code now in
infrun.c. GDBserver just has to report the events and do a little
bookkeeping.
Implementation includes:
* enabling VFORK events by adding ptrace options for VFORK and VFORK_DONE
to linux-low.c:linux_low_ptrace_options.
* handling VFORK and VFORK_DONE events in linux-low.c:handle_extended_wait
and reporting them to GDB.
* including VFORK and VFORK_DONE events in the predicate
linux-low.c:extended_event_reported.
* adding support for VFORK and VFORK_DONE events in RSP by adding stop
reasons "vfork" and "vforkdone" to the 'T' Stop Reply Packet in both
gdbserver/remote-utils.c and gdb/remote.c.
Tested on x64 Ubuntu Lucid, native, remote, extended-remote.
gdb/gdbserver/ChangeLog:
* linux-low.c (handle_extended_wait): Handle PTRACE_EVENT_FORK and
PTRACE_EVENT_VFORK_DONE.
(linux_low_ptrace_options, extended_event_reported): Add vfork
events.
* remote-utils.c (prepare_resume_reply): New stop reasons "vfork"
and "vforkdone" for RSP 'T' Stop Reply Packet.
* server.h (report_vfork_events): Declare
global variable.
gdb/ChangeLog:
* remote.c (remove_vfork_event_p): New function.
(remote_follow_fork): Add vfork event type to event checking.
(remote_parse_stop_reply): New stop reasons "vfork" and
"vforkdone" for RSP 'T' Stop Reply Packet.
This patch implements the architecture-specific pieces of follow-fork
for remote and extended-remote Linux targets, which in the current
implementation copyies the parent's debug register state into the new
child's data structures. This is required for x86, arm, aarch64, and
mips.
This follows the native implementation as closely as possible by
implementing a new linux_target_ops function 'new_fork', which is
analogous to 'linux_nat_new_fork' in linux-nat.c. In gdbserver, the debug
registers are stored in the process list, instead of an
architecture-specific list, so the function arguments are process_info
pointers instead of an lwp_info and a pid as in the native implementation.
In the MIPS implementation the debug register mirror is stored differently
from x86, ARM, and aarch64, so instead of doing a simple structure assignment
I had to clone the list of watchpoint structures.
Tested using gdb.threads/watchpoint-fork.exp on x86, and ran manual tests
on a MIPS board and an ARM board. Aarch64 hasn't been tested.
gdb/gdbserver/ChangeLog:
* linux-aarch64-low.c (aarch64_linux_new_fork): New function.
(the_low_target) <new_fork>: Initialize new member.
* linux-arm-low.c (arm_new_fork): New function.
(the_low_target) <new_fork>: Initialize new member.
* linux-low.c (handle_extended_wait): Call new target function
new_fork.
* linux-low.h (struct linux_target_ops) <new_fork>: New member.
* linux-mips-low.c (mips_add_watchpoint): New function
extracted from mips_insert_point.
(the_low_target) <new_fork>: Initialize new member.
(mips_linux_new_fork): New function.
(mips_insert_point): Call mips_add_watchpoint.
* linux-x86-low.c (x86_linux_new_fork): New function.
(the_low_target) <new_fork>: Initialize new member.
This patch implements basic support for follow-fork and detach-on-fork on
extended-remote Linux targets. Only 'fork' is supported in this patch;
'vfork' support is added n a subsequent patch. This patch depends on
the previous patches in the patch series.
Sufficient extended-remote functionality has been implemented here to pass
gdb.base/multi-forks.exp, as well as gdb.base/foll-fork.exp with the
catchpoint tests commented out. Some other fork tests fail with this
patch because it doesn't provide the architecture support needed for
watchpoint inheritance or fork catchpoints.
The implementation follows the same general structure as for the native
implementation as much as possible.
This implementation includes:
* enabling fork events in linux-low.c in initialize_low and
linux_enable_extended_features
* handling fork events in gdbserver/linux-low.c:handle_extended_wait
- when a fork event occurs in gdbserver, we must do the full creation
of the new process, thread, lwp, and breakpoint lists. This is
required whether or not the new child is destined to be
detached-on-fork, because GDB will make target calls that require all
the structures. In particular we need the breakpoint lists in order
to remove the breakpoints from a detaching child. If we are not
detaching the child we will need all these structures anyway.
- as part of this event handling we store the target_waitstatus in a new
member of the parent lwp_info structure, 'waitstatus'. This
is used to store extended event information for reporting to GDB.
- handle_extended_wait is given a return value, denoting whether the
handled event should be reported to GDB. Previously it had only
handled clone events, which were never reported.
* using a new predicate in gdbserver to control handling of the fork event
(and eventually all extended events) in linux_wait_1. The predicate,
extended_event_reported, checks a target_waitstatus.kind for an
extended ptrace event.
* implementing a new RSP 'T' Stop Reply Packet stop reason: "fork", in
gdbserver/remote-utils.c and remote.c.
* implementing new target and RSP support for target_follow_fork with
target extended-remote. (The RSP components were actually defined in
patch 1, but they see their first use here).
- remote target routine remote_follow_fork, which just sends the 'D;pid'
detach packet to detach the new fork child cleanly. We can't just
call target_detach because the data structures for the forked child
have not been allocated on the host side.
Tested on x64 Ubuntu Lucid, native, remote, extended-remote.
gdb/gdbserver/ChangeLog:
* linux-low.c (handle_extended_wait): Implement return value,
rename argument 'event_child' to 'event_lwp', handle
PTRACE_EVENT_FORK, call internal_error for unrecognized event.
(linux_low_ptrace_options): New function.
(linux_low_filter_event): Call linux_low_ptrace_options,
use different argument fo linux_enable_event_reporting,
use return value from handle_extended_wait.
(extended_event_reported): New function.
(linux_wait_1): Call extended_event_reported and set
status to report fork events.
(linux_write_memory): Add pid to debug message.
(reset_lwp_ptrace_options_callback): New function.
(linux_handle_new_gdb_connection): New function.
(linux_target_ops): Initialize new structure member.
* linux-low.h (struct lwp_info) <waitstatus>: New member.
* lynx-low.c: Initialize new structure member.
* remote-utils.c (prepare_resume_reply): Implement stop reason
"fork" for "T" stop message.
* server.c (handle_query): Call handle_new_gdb_connection.
* server.h (report_fork_events): Declare global flag.
* target.h (struct target_ops) <handle_new_gdb_connection>:
New member.
(target_handle_new_gdb_connection): New macro.
* win32-low.c: Initialize new structure member.
gdb/ChangeLog:
* linux-nat.c (linux_nat_ptrace_options): New function.
(linux_init_ptrace, wait_lwp, linux_nat_filter_event):
Call linux_nat_ptrace_options and use different argument to
linux_enable_event_reporting.
(_initialize_linux_nat): Delete call to
linux_ptrace_set_additional_flags.
* nat/linux-ptrace.c (current_ptrace_options): Rename to
supported_ptrace_options.
(additional_flags): Delete variable.
(linux_check_ptrace_features): Use supported_ptrace_options.
(linux_test_for_tracesysgood, linux_test_for_tracefork):
Likewise, and remove additional_flags check.
(linux_enable_event_reporting): Change 'attached' argument to
'options'. Use supported_ptrace_options.
(ptrace_supports_feature): Change comment. Use
supported_ptrace_options.
(linux_ptrace_set_additional_flags): Delete function.
* nat/linux-ptrace.h (linux_ptrace_set_additional_flags):
Delete function prototype.
* remote.c (remote_fork_event_p): New function.
(remote_detach_pid): New function.
(remote_detach_1): Call remote_detach_pid, don't mourn inferior
if doing detach-on-fork.
(remote_follow_fork): New function.
(remote_parse_stop_reply): Handle new "T" stop reason "fork".
(remote_pid_to_str): Print "process" strings for pid/0/0 ptids.
(init_extended_remote_ops): Initialize to_follow_fork.
This patch implements gdbserver routines to clone the breakpoint lists of a
process, duplicating them for another process. In gdbserver, each process
maintains its own independent breakpoint list. When a fork call creates a
child, all of the breakpoints currently inserted in the parent process are
also inserted in the child process, but there is nothing to describe them
in the data structures related to the child. The child must have a
breakpoint list describing them so that they can be removed (if detaching)
or recognized (if following). Implementation is a mechanical process of
just cloning the lists in several new functions in gdbserver/mem-break.c.
Tested by building, since none of the new functions are called yet. This
was tested with another patch in the series that implements follow-fork.
gdb/gdbserver/ChangeLog:
* mem-break.c (APPEND_TO_LIST): Define macro.
(clone_agent_expr): New function.
(clone_one_breakpoint): New function.
(clone_all_breakpoints): New function.
* mem-break.h: Declare new functions.
This patch implements a mechanism for GDB to determine whether fork
events are supported in gdbserver. This is a preparatory patch for
remote fork and exec event support.
Two new RSP packets are defined to represent fork and vfork event
support. These packets are used just like PACKET_multiprocess_feature
to denote whether the corresponding event is supported. GDB sends
fork-events+ and vfork-events+ to gdbserver to inquire about fork
event support. If the response enables these packets, then GDB
knows that gdbserver supports the corresponding events and will
enable them.
Target functions used to query for support are included along with
each new packet.
In order for gdbserver to know whether the events are supported at the
point where the qSupported packet arrives, the code in nat/linux-ptrace.c
had to be reorganized. Previously it would test for fork/exec event
support, then enable the events using the pid of the inferior. When the
qSupported packet arrives there may not be an inferior. So the mechanism
was split into two parts: a function that checks whether the events are
supported, called when gdbserver starts up, and another that enables the
events when the inferior stops for the first time.
Another gdbserver change was to add some global variables similar to
multi_process, one per new packet. These are used to control whether
the corresponding fork events are enabled. If GDB does not inquire
about the event support in the qSupported packet, then gdbserver will
not set these "report the event" flags. If the flags are not set, the
events are ignored like they were in the past. Thus, gdbserver will
never send fork event notification to an older GDB that doesn't
recognize fork events.
Tested on Ubuntu x64, native/remote/extended-remote, and as part of
subsequent patches in the series.
gdb/gdbserver/ChangeLog:
* linux-low.c (linux_supports_fork_events): New function.
(linux_supports_vfork_events): New function.
(linux_target_ops): Initialize new structure members.
(initialize_low): Call linux_check_ptrace_features.
* lynx-low.c (lynx_target_ops): Initialize new structure
members.
* server.c (report_fork_events, report_vfork_events):
New global flags.
(handle_query): Add new features to qSupported packet and
response.
(captured_main): Initialize new global variables.
* target.h (struct target_ops) <supports_fork_events>:
New member.
<supports_vfork_events>: New member.
(target_supports_fork_events): New macro.
(target_supports_vfork_events): New macro.
* win32-low.c (win32_target_ops): Initialize new structure
members.
gdb/ChangeLog:
* nat/linux-ptrace.c (linux_check_ptrace_features): Change
from static to extern.
* nat/linux-ptrace.h (linux_check_ptrace_features): Declare.
* remote.c (anonymous enum): <PACKET_fork_event_feature,
* PACKET_vfork_event_feature>: New enumeration constants.
(remote_protocol_features): Add table entries for new packets.
(remote_query_supported): Add new feature queries to qSupported
packet.
(_initialize_remote): Exempt new packets from the requirement
to have 'set remote' commands.
This commit allows GDB to determine filenames of main executables
when debugging using remote stubs without multiprocess extensions.
The qXfer:exec-file:read packet is extended to allow an empty
annex, with the meaning that the remote stub should supply the
filename of whatever it thinks is the current process.
gdb/ChangeLog:
* remote.c (remote_add_inferior): Call exec_file_locate_attach
for fake PIDs as well as real ones.
(remote_pid_to_exec_file): Send empty annex if PID is fake.
gdb/doc/ChangeLog:
* gdb.texinfo (General Query Packets): Document
qXfer:exec-file:read with empty annex.
gdb/gdbserver/ChangeLog:
* server.c (handle_qxfer_exec_file): Use current process
if annex is empty.
Disp16 and Disp32 aren't supported by direct branches in 64-bit mode.
This patch removes them from 64-bit direct branches.
* opcodes/i386-opc.tbl (call): Remove Disp16|Disp32 from 64-bit
direct branch.
(jmp): Likewise.
* i386-tbl.h: Regenerated.
Mixing target and not-target directives can be used to run for x86_64-*-*
target while skipping x86_64-*-gnux32 target. This patch allows mixing
target and not-target directives. It is used to skip elfedit-1 for
x86_64-*-gnux32.
* binutils-all/elfedit-1.d: Skip x86_64-*-gnux32.
* lib/utils-lib.exp (run_dump_test): Allow mixing target and
not-target directives.
