Without the code portion of the patch, we get these failures:
FAIL: gdb.base/break-unload-file.exp: always-inserted on: break: continue
FAIL: gdb.base/break-unload-file.exp: always-inserted on: hbreak: continue
FAIL: gdb.base/sym-file.exp: stale bkpts: continue to breakpoint: end here
They all looks like random SIGTRAPs:
continue
Continuing.
Program received signal SIGTRAP, Trace/breakpoint trap.
0x0000000000400541 in foo () at ../../../src/gdb/testsuite/gdb.base/break-unload-file.c:21
21 }
(gdb) FAIL: gdb.base/break-unload-file.exp: always-inserted on: break: continue
(This is a regression caused by the remove-symbol-file command
series.)
break-unload-file.exp is about having breakpoints inserted, and then
doing "file". I caught this while writing a test that does "file
PROGRAM", while PROGRAM was already loaded, which internally does
"file" first, because I wanted to force a breakpoint_re_set, but the
test is more explicit in case GDB ever optimizes out that re-set.
The problem is that unloading the file with "file" ends up in
disable_breakpoints_in_freed_objfile, which marks all breakpoint
locations of the objfile as both shlib_disabled, _and_ clears the
inserted flag, without actually removing the breakpoints from the
inferior. Now, usually, in all-stop, breakpoints will already be
removed from the inferior before the user can issue the "file"
command, but, with non-stop, or breakpoints always-inserted on mode,
breakpoints stay inserted even while the user has the prompt. In the
latter case, then, if we let the program continue, and it executes the
address where we had previously set the breakpoint, it'll actually
execute the breakpoint instruction that we left behind...
Now, one issue is that the intent of
disable_breakpoints_in_freed_objfile is really to handle the unloading
of OBJF_USERLOADED objfiles. These are objfiles that were added with
add-symbol-file and that are removed with remove-symbol-file.
"add-symbol-file"'s docs in the manual clearly say these commands are
used to let GDB know about dynamically loaded code:
You would use this command when @var{filename} has been dynamically
loaded (by some other means) into the program that is running.
Similarly, the online help says:
(gdb) help add-symbol-file
Load symbols from FILE, assuming FILE has been dynamically loaded.
So it makes sense to, like when shared libraries are unloaded through
the generic solib machinery, mark the breakpoint locations as
shlib_disabled. But, the "file" command is not about dynamically
loaded code, it's about the main program. So the patch makes
disable_breakpoints_in_freed_objfile skip all objfiles but
OBJF_USERLOADED ones, thus skipping the main objfile.
Then, the reason that disable_breakpoints_in_freed_objfile was
clearing the inserted flag isn't clear, but likely to avoid breakpoint
removal errors, assuming remove-symbol-file was called after the
dynamic object was already unmapped from the inferior. In that case,
it'd okay to simply clear the inserted flag, but not so if the user
for example does remove-symbol-file to remove the library because he
made a mistake in the library's address, and wants to re-do
add-symbol-file with the correct address.
To address all that, I propose an alternative implementation, that
handles both cases. The patch includes changes to sym-file.exp to
cover them.
This implementation leaves the inserted flag alone, and handles
breakpoint insertion/removal failure gracefully when the locations are
in OBJF_USERLOADED objfiles, just like we handle insertion/removal
failure gracefully for locations in shared libraries.
To try to make sure we aren't patching back stale shadow memory
contents into the inferior, in case the program mapped a different
library at the same address where we had the breakpoint, without the
user having had a chance of remove-symbol-file'ing before, this adds a
new memory_validate_breakpoint function that checks if the breakpoint
instruction is still in memory. ppc_linux_memory_remove_breakpoint
does this unconditionally for all memory breakpoints, and questions
whether memory_remove_breakpoint should be changed to do this for all
breakpoints. Possibly yes, though I'm not certain, hence this
baby-steps patch.
Tested on x86_64 Fedora 17, native and gdbserver.
gdb/
2014-04-23 Pedro Alves <palves@redhat.com>
* breakpoint.c (insert_bp_location): Tolerate errors if the
breakpoint is set in a user-loaded objfile.
(remove_breakpoint_1): Likewise. Also tolerate errors if the
location is marked shlib_disabled. If the breakpoint is set in a
user-loaded objfile is a GDB-side memory breakpoint, validate it
before uninsertion. (disable_breakpoints_in_freed_objfile): Skip
non-OBJF_USERLOADED objfiles. Don't clear the location's inserted
flag.
* mem-break.c (memory_validate_breakpoint): New function.
* objfiles.c (userloaded_objfile_contains_address_p): New
function.
* objfiles.h (userloaded_objfile_contains_address_p): Declare.
* target.h (memory_validate_breakpoint): New declaration.
gdb/testsuite/
2014-04-23 Pedro Alves <palves@redhat.com>
* gdb.base/break-unload-file.c: New file.
* gdb.base/break-unload-file.exp: New file.
* gdb.base/sym-file-lib.c (baz): New function.
* gdb.base/sym-file-loader.c (struct segment) <mapped_size>: New
field.
(load): Store the segment's mapped size.
(unload): New function.
(unload_shlib): New function.
* gdb.base/sym-file-loader.h (unload_shlib): New declaration.
* gdb.base/sym-file-main.c (main): Unload, and reload the library,
set a breakpoint at baz, and call it.
* gdb.base/sym-file.exp: New tests for stale breakpoint
instructions.
A patch in the target cleanup series caused a regression when using
record with target-async. Version 4 of the patch is here:
https://sourceware.org/ml/gdb-patches/2014-03/msg00159.html
The immediate problem is that record supplies to_can_async_p and
to_is_async_p methods, but does not supply a to_async method. So,
when target-async is set, record claims to support async -- but if the
underlying target does not support async, then the to_async method
call will end up in that method's default implementation, namely
tcomplain.
This worked previously because the record target used to provide a
to_async method; one that (erroneously, only at push time) checked the
other members of the target stack, and then simply dropped to_async
calls in the "does not implement async" case.
My first thought was to simply drop tcomplain as the default for
to_async. This works, but Pedro pointed out that the only reason
record has to supply to_can_async_p and to_is_async_p is that these
default to using the find_default_run_target machinery -- and these
defaults are only needed by "run" and "attach".
So, a nicer solution presents itself: change run and attach to
explicitly call into the default run target when needed; and change
to_is_async_p and to_can_async_p to default to "return 0". This makes
the target stack simpler to use and lets us remove the method
implementations from record. This is also in harmony with other plans
for the target stack; namely trying to reduce the impact of
find_default_run_target. This approach makes it clear that
find_default_is_async_p is not needed -- it is asking whether a target
that may not even be pushed is actually async, which seems like a
nonsensical question.
While an improvement, this approach proved to introduce the same bug
when using the core target. Looking a bit deeper, the issue is that
code in "attach" and "run" may need to use either the current target
stack or the default run target -- but different calls into the target
API in those functions could wind up querying different targets.
This new patch makes the target to use more explicit in "run" and
"attach". Then these commands explicitly make the needed calls
against that target. This ensures that a single target is used for
all relevant operations. This lets us remove a couple find_default_*
functions from various targets, including the dummy target. I think
this is a decent understandability improvement.
One issue I see with this patch is that the new calls in "run" and
"attach" are not very much like the rest of the target API. I think
fundamentally this is due to bad factoring in the target API, which
may need to be fixed for multi-target. Tackling that seemed ambitious
for a regression fix.
While working on this I noticed that there don't seem to be any test
cases that involve both target-async and record, so this patch changes
break-precsave.exp to add some. It also changes corefile.exp to add
some target-async tests; these pass with current trunk and with this
patch applied, but fail with the v1 patch.
This patch differs from v4 in that it moves initialization of
to_can_async_p and to_supports_non_stop into inf-child, adds some
assertions to complete_target_initialization, and adds some comments
to target.h.
Built and regtested on x86-64 Fedora 20.
2014-03-12 Tom Tromey <tromey@redhat.com>
* inf-child.c (return_zero): New function.
(inf_child_target): Set to_can_async_p, to_supports_non_stop.
* aix-thread.c (aix_thread_inferior_created): New function.
(aix_thread_attach): Remove.
(init_aix_thread_ops): Don't set to_attach.
(_initialize_aix_thread): Register inferior_created observer.
* corelow.c (init_core_ops): Don't set to_attach or
to_create_inferior.
* exec.c (init_exec_ops): Don't set to_attach or
to_create_inferior.
* infcmd.c (run_command_1): Use find_run_target. Make direct
target calls.
(attach_command): Use find_attach_target. Make direct target
calls.
* record-btrace.c (init_record_btrace_ops): Don't set
to_create_inferior.
* record-full.c (record_full_can_async_p, record_full_is_async_p):
Remove.
(init_record_full_ops, init_record_full_core_ops): Update. Don't
set to_create_inferior.
* target.c (complete_target_initialization): Add assertion.
(target_create_inferior): Remove.
(find_default_attach, find_default_create_inferior): Remove.
(find_attach_target, find_run_target): New functions.
(find_default_is_async_p, find_default_can_async_p)
(target_supports_non_stop, target_attach): Remove.
(init_dummy_target): Don't set to_create_inferior or
to_supports_non_stop.
* target.h (struct target_ops) <to_attach>: Add comment. Remove
TARGET_DEFAULT_FUNC.
<to_create_inferior>: Add comment.
<to_can_async_p, to_is_async_p, to_supports_non_stop>: Use
TARGET_DEFAULT_RETURN.
<to_can_async_p, to_supports_non_stop, to_can_run>: Add comments.
(find_attach_target, find_run_target): Declare.
(target_create_inferior): Remove.
(target_has_execution_1): Update comment.
(target_supports_non_stop): Remove.
* target-delegates.c: Rebuild.
2014-03-12 Tom Tromey <tromey@redhat.com>
* gdb.base/corefile.exp (corefile_test_run, corefile_test_attach):
New procs. Add target-async tests.
* gdb.reverse/break-precsave.exp (precsave_tests): New proc.
Add target-async tests.
This function is for simple breakpoint. So I post a patch to remove "hardware".
Thanks,
Hui
2014-03-10 Hui Zhu <hui@codesourcery.com>
* target.h (target_insert_breakpoint): Remove "hardware" from its
comments.
Expand a bit the comments to answer some questions I had when looking
at why a target of mine would not have some default methods set.
gdb/ChangeLog:
* target.h (complete_target_initialization, add_target):
Add comment.
This patch is to change the default implementation of to_traceframe_info
from 'return NULL' to tcomplain, which is intended. If new target
supports tracepoint, this method should be implemented, otherwise,
an error is thrown.
gdb:
2014-03-06 Yao Qi <yao@codesourcery.com>
* target.h (struct target_ops) <to_traceframe_info>: Use
TARGET_DEFAULT_NORETURN (tcomplain ()).
* target-delegates.c: Regenerated.
As no target uses it anymore, it can finally go away.
After removing the deprecated_xfer_memory handling from
default_xfer_partial, we can delete the latter, because the only thing
it does is delegate to the target beneath unconditionally, which is
what the delegator installed by target-delegates.c will do for us if
no to_xfer_partial method is installed.
This was the last user of de_fault, so that goes away too.
Tested on x86_64 Fedora 17.
gdb/
2014-02-26 Pedro Alves <palves@redhat.com>
* target.c (complete_target_initialization): Don't install
default_xfer_partial as to_xfer_partial hook.
(nomemory): Delete.
(update_current_target): Don't INHERIT nor de_fault
deprecated_xfer_memory. Delete de_fault macro.
(default_xfer_partial, deprecated_debug_xfer_memory): Delete.
(setup_target_debug): Don't install a deprecated_xfer_memory hook.
* target.h (struct target_ops) <deprecated_xfer_memory>: Delete
field.
This removes target_ignore, which isn't used any more.
2014-02-25 Tom Tromey <tromey@redhat.com>
* target.h (target_ignore): Don't declare.
* target.c (target_ignore): Remove.
Nowadays, TARGET_XFER_E_UNAVAILABLE isn't regarded as an error in
to_xfer_partial interface, so _E_ looks odd. This patch is to
replace TARGET_XFER_E_UNAVAILABLE with TARGET_XFER_UNAVAILABLE,
and change its value from -2 to 2. Since there is no comparison
on the value of 'enum target_xfer_status', so it should be safe.
gdb:
2014-02-24 Yao Qi <yao@codesourcery.com>
* target.h (enum target_xfer_status)
<TARGET_XFER_E_UNAVAILABLE>: Rename it to ...
<TARGET_XFER_UNAVAILABLE>: ... it with setting value 2
explicitly. New.
* corefile.c (memory_error_message): User updated.
* exec.c (section_table_read_available_memory): Likewise.
* record-btrace.c (record_btrace_xfer_partial): Likewise.
* target.c (target_xfer_status_to_string): Likewise.
(raw_memory_xfer_partial): Likewise.
(memory_xfer_partial_1, target_xfer_partial): Likewise.
* valops.c (read_value_memory): Likewise.
* exec.h: Update comments.
This patch tweaks target_xfer_status_to_string on comments and argument
name.
gdb:
2014-02-24 Yao Qi <yao@codesourcery.com>
* target.c (target_xfer_status_to_string): Rename argument err
to status.
* target.h (target_xfer_status_to_string): Update declaration.
Replace target_xfer_error_to_string with
target_xfer_status_to_string in comment.
This patch removes macro TARGET_XFER_STATUS_ERROR_P, as Pedro pointed
out during patches review that TARGET_XFER_STATUS_ERROR_P tends to
be unnecessary.
gdb:
2014-02-24 Yao Qi <yao@codesourcery.com>
* target.h (TARGET_XFER_STATUS_ERROR_P): Remove.
* corefile.c (read_memory): Adjusted.
* target.c (target_write_with_progress): Adjusted.
As we migrate to the new to_xfer_partial interface, some of previous
tweaks become unnecessary, we don't have to check traceframe is
selected in each target implementation, so this patch below is
reverted.
[PATCH] Send qXfer:traceframe-info:read when traceframe is selected.
https://sourceware.org/ml/gdb-patches/2013-10/msg00752.html
Third, to_traceframe_info is only called when traceframe is selected,
that means it is only called when target is remote, tfile or ctf, so
this patch can be partially reverted,
https://sourceware.org/ml/gdb-patches/2013-04/msg00000.html
gdb:
2014-02-23 Yao Qi <yao@codesourcery.com>
Revert two patches:
2013-10-25 Yao Qi <yao@codesourcery.com>
* remote.c (remote_traceframe_info): Return early if
traceframe is not selected.
2013-07-19 Yao Qi <yao@codesourcery.com>
* target.c (update_current_target): Change the default action
of 'to_traceframe_info' from tcomplain to return_zero.
* target.h (struct target_ops) <to_traceframe_info>: Add more
comments.
This converts to_get_unwinder and to_get_tailcall_unwinder to methods
and arranges for them to use the new delegation scheme.
This just lets us avoid having a differing style (neither new-style
nor INHERIT) of delegation in the tree.
2014-02-19 Tom Tromey <tromey@redhat.com>
* target.c (target_get_unwinder): Rewrite.
(target_get_tailcall_unwinder): Rewrite.
* record-btrace.c (record_btrace_to_get_unwinder): New function.
(record_btrace_to_get_tailcall_unwinder): New function.
(init_record_btrace_ops): Update.
* target.h (struct target_ops) <to_get_unwinder,
to_get_tailcall_unwinder>: Now function pointers. Use
TARGET_DEFAULT_RETURN.
This converts to_decr_pc_after_break to the new style of delegation,
removing forward_target_decr_pc_after_break.
2014-02-19 Tom Tromey <tromey@redhat.com>
* record-btrace.c (record_btrace_decr_pc_after_break): Delegate
directly.
* target-delegates.c: Rebuild.
* target.h (struct target_ops) <to_decr_pc_after_break>: Use
TARGET_DEFAULT_FUNC.
* target.c (default_target_decr_pc_after_break): Rename from
forward_target_decr_pc_after_break. Simplify.
(target_decr_pc_after_break): Rely on delegation.
This changes instances of TARGET_DEFAULT_RETURN(0) to
TARGET_DEFAULT_RETURN(NULL) when appropriate. The use of "0" was a
relic from an earlier implementation of make-target-delegates; and I
didn't want to go back through the long patch series, fixing up
conflicts, just to change this small detail.
2014-02-19 Tom Tromey <tromey@redhat.com>
* target-delegates.c: Rebuild.
* target.h (struct target_ops) <to_extra_thread_info,
to_thread_name, to_pid_to_exec_file, to_get_section_table,
to_memory_map, to_read_description, to_traceframe_info>: Use NULL,
not 0, in TARGET_DEFAULT_RETURN.
This switches to_read_description to the "new normal" delegation
scheme. This one was a bit trickier than the other changes due to the
way that target_read_description handled delegation. I examined all
the target implementations of to_read_description and changed the ones
returning NULL to instead delegate.
2014-02-19 Tom Tromey <tromey@redhat.com>
* arm-linux-nat.c (arm_linux_read_description): Delegate when
needed.
* corelow.c (core_read_description): Delegate when needed.
* remote.c (remote_read_description): Delegate when needed.
* target-delegates.c: Rebuild.
* target.c (target_read_description): Rewrite.
* target.h (struct target_ops) <to_read_description>: Update
comment. Use TARGET_DEFAULT_RETURN.
