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This commit brings all the changes made by running gdb/copyright.py
as per GDB's Start of New Year Procedure.
For the avoidance of doubt, all changes in this commits were
performed by the script.
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This commit was originally part of this patch series:
(v1): https://sourceware.org/pipermail/gdb-patches/2021-May/179357.html
(v2): https://sourceware.org/pipermail/gdb-patches/2021-June/180208.html
(v3): https://sourceware.org/pipermail/gdb-patches/2021-July/181028.html
However, that series is being held up in review, so I wanted to break
out some of the non-related fixes in order to get these merged.
This commit addresses two semi-related issues, both of which are
problems exposed by using 'set debug frame on'.
The first issue is in frame.c in get_prev_frame_always_1, and was
introduced by this commit:
commit a05a883fbaba69d0f80806e46a9457727fcbe74c
Date: Tue Jun 29 12:03:50 2021 -0400
gdb: introduce frame_debug_printf
This commit replaced fprint_frame with frame_info::to_string.
However, the former could handle taking a nullptr while the later, a
member function, obviously requires a non-nullptr in order to make the
function call. In one place we are not-guaranteed to have a
non-nullptr, and so, there is the possibility of triggering undefined
behaviour.
The second issue addressed in this commit has existed for a while in
GDB, and would cause this assertion:
gdb/frame.c:622: internal-error: frame_id get_frame_id(frame_info*): Assertion `fi->this_id.p != frame_id_status::COMPUTING' failed.
We attempt to get the frame_id for a frame while we are computing the
frame_id for that same frame.
What happens is that when GDB stops we create a frame_info object for
the sentinel frame (frame #-1) and then we attempt to unwind this
frame to create a frame_info object for frame #0.
In the test case used here to expose the issue we have created a
Python frame unwinder. In the Python unwinder we attemt to read the
program counter register.
Reading this register will initially create a lazy register value.
The frame-id stored in the lazy register value will be for the
sentinel frame (lazy register values hold the frame-id for the frame
from which the register will be unwound).
However, the Python unwinder does actually want to examine the value
of the program counter, and so the lazy register value is resolved
into a non-lazy value. This sends GDB into value_fetch_lazy_register
in value.c.
Now, inside this function, if 'set debug frame on' is in effect, then
we want to print something like:
frame=%d, regnum=%d(%s), ....
Where 'frame=%d' will be the relative frame level of the frame for
which the register is being fetched, so, in this case we would expect
to see 'frame=0', i.e. we are reading a register as it would be in
frame #0. But, remember, the lazy register value actually holds the
frame-id for frame #-1 (the sentinel frame).
So, to get the frame_info for frame #0 we used to call:
frame = frame_find_by_id (VALUE_FRAME_ID (val));
Where VALUE_FRAME_ID is:
#define VALUE_FRAME_ID(val) (get_prev_frame_id_by_id (VALUE_NEXT_FRAME_ID (val)))
That is, we start with the frame-id for the next frame as obtained by
VALUE_NEXT_FRAME_ID, then call get_prev_frame_id_by_id to get the
frame-id of the previous frame.
The get_prev_frame_id_by_id function finds the frame_info for the
given frame-id (in this case frame #-1), calls get_prev_frame to get
the previous frame, and then calls get_frame_id.
The problem here is that calling get_frame_id requires that we know
the frame unwinder, so then have to try each frame unwinder in turn,
which would include the Python unwinder.... which is where we started,
and thus we have a loop!
To prevent this loop GDB has an assertion in place, which is what
actually triggers.
Solving the assertion failure is pretty easy, if we consider the code
in value_fetch_lazy_register and get_prev_frame_id_by_id then what we
do is:
1. Start with a frame_id taken from a value,
2. Lookup the corresponding frame,
3. Find the previous frame,
4. Get the frame_id for that frame, and
5. Lookup the corresponding frame
6. Print the frame's level
Notice that steps 3 and 5 give us the exact same result, step 4 is
just wasted effort. We could shorten this process such that we drop
steps 4 and 5, thus:
1. Start with a frame_id taken from a value,
2. Lookup the corresponding frame,
3. Find the previous frame,
6. Print the frame's level
This will give the exact same frame as a result, and this is what I
have done in this patch by removing the use of VALUE_FRAME_ID from
value_fetch_lazy_register.
Out of curiosity I looked to see how widely VALUE_FRAME_ID was used,
and saw it was only used in one other place in valops.c:value_assign,
where, once again, we take the result of VALUE_FRAME_ID and pass it to
frame_find_by_id, thus introducing a redundant frame_id lookup.
I don't think the value_assign case risks triggering the assertion
though, as we are unlikely to call value_assign while computing the
frame_id for a frame, however, we could make value_assign slightly
more efficient, with no real additional complexity, by removing the
use of VALUE_FRAME_ID.
So, in this commit, I completely remove VALUE_FRAME_ID, and replace it
with a use of VALUE_NEXT_FRAME_ID, followed by a direct call to
get_prev_frame_always, this should make no difference in either case,
and resolves the assertion issue from value.c.
As I said, this patch was originally part of another series, the
original test relied on the fixes in that original series. However, I
was able to create an alternative test for this issue by enabling
frame debug within an existing test script.
This commit probably fixes bug PR gdb/27938, though the bug doesn't
have a reproducer attached so it is not possible to know for sure.
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=27938
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Introduce FRAME_SCOPED_DEBUG_ENTER_EXIT and use it to print enter/exit
messages in important frame-related functions. I think this helps
understand which lower-level operations are done as part of which
higher-level operation. And it helps visually skip over a higher-level
operation you are not interested in.
Here's an example, combined with some py-unwind messages:
[frame] frame_unwind_find_by_frame: enter
[frame] frame_unwind_find_by_frame: this_frame=0
[frame] frame_unwind_try_unwinder: trying unwinder "dummy"
[frame] frame_unwind_try_unwinder: no
[frame] frame_unwind_try_unwinder: trying unwinder "dwarf2 tailcall"
[frame] frame_unwind_try_unwinder: no
[frame] frame_unwind_try_unwinder: trying unwinder "inline"
[frame] frame_unwind_try_unwinder: no
[frame] frame_unwind_try_unwinder: trying unwinder "jit"
[frame] frame_unwind_try_unwinder: no
[frame] frame_unwind_try_unwinder: trying unwinder "python"
[py-unwind] pyuw_sniffer: enter
[frame] frame_unwind_register_value: enter
[frame] frame_unwind_register_value: frame=-1, regnum=7(rsp)
[frame] frame_unwind_register_value: -> register=7 bytes=[40ddffffff7f0000]
[frame] frame_unwind_register_value: exit
[py-unwind] pyuw_sniffer: frame=0, sp=0x7fffffffdd40, pc=0x5555555551ec
[frame] frame_id_p: l={stack=<sentinel>,!code,special=0x0000000000000000} -> 1
[frame] frame_id_p: l={stack=<sentinel>,!code,special=0x0000000000000000} -> 1
[frame] frame_id_eq: l={stack=<sentinel>,!code,special=0x0000000000000000}, r={stack=<sentinel>,!code,special=0x0000000000000000} -> 1
[frame] frame_unwind_register_value: enter
[frame] frame_unwind_register_value: frame=-1, regnum=6(rbp)
[frame] frame_unwind_register_value: -> register=6 bytes=[50ddffffff7f0000]
[frame] frame_unwind_register_value: exit
[frame] frame_id_p: l={stack=<sentinel>,!code,special=0x0000000000000000} -> 1
[frame] frame_id_eq: l={stack=<sentinel>,!code,special=0x0000000000000000}, r={stack=<sentinel>,!code,special=0x0000000000000000} -> 1
[frame] get_prev_frame: enter
[frame] get_prev_frame_always_1: enter
[frame] get_prev_frame_always_1: this_frame=-1
[frame] get_prev_frame_always_1: -> {level=0,type=NORMAL_FRAME,unwind=0x5588ee3d17c0,pc=0x5555555551ec,id=<not computed>,func=<unknown>} // cached
[frame] get_prev_frame_always_1: exit
[frame] get_prev_frame: exit
[frame] value_fetch_lazy_register: (frame=0, regnum=6(rbp), ...) -> register=6 bytes=[50ddffffff7f0000]
[frame] frame_id_p: l={stack=<sentinel>,!code,special=0x0000000000000000} -> 1
[frame] frame_id_p: l={stack=<sentinel>,!code,special=0x0000000000000000} -> 1
[frame] frame_id_eq: l={stack=<sentinel>,!code,special=0x0000000000000000}, r={stack=<sentinel>,!code,special=0x0000000000000000} -> 1
[frame] frame_unwind_register_value: enter
[frame] frame_unwind_register_value: frame=-1, regnum=7(rsp)
[frame] frame_unwind_register_value: -> register=7 bytes=[40ddffffff7f0000]
[frame] frame_unwind_register_value: exit
[frame] frame_id_p: l={stack=<sentinel>,!code,special=0x0000000000000000} -> 1
[frame] frame_id_eq: l={stack=<sentinel>,!code,special=0x0000000000000000}, r={stack=<sentinel>,!code,special=0x0000000000000000} -> 1
[frame] get_prev_frame: enter
[frame] get_prev_frame_always_1: enter
[frame] get_prev_frame_always_1: this_frame=-1
[frame] get_prev_frame_always_1: -> {level=0,type=NORMAL_FRAME,unwind=0x5588ee3d1824,pc=0x5555555551ec,id=<not computed>,func=<unknown>} // cached
[frame] get_prev_frame_always_1: exit
[frame] get_prev_frame: exit
[frame] value_fetch_lazy_register: (frame=0, regnum=7(rsp), ...) -> register=7 bytes=[40ddffffff7f0000]
[frame] frame_id_p: l={stack=<sentinel>,!code,special=0x0000000000000000} -> 1
[frame] frame_id_p: l={stack=<sentinel>,!code,special=0x0000000000000000} -> 1
[frame] frame_id_eq: l={stack=<sentinel>,!code,special=0x0000000000000000}, r={stack=<sentinel>,!code,special=0x0000000000000000} -> 1
[frame] frame_unwind_register_value: enter
[frame] frame_unwind_register_value: frame=-1, regnum=16(rip)
[frame] frame_unwind_register_value: -> register=16 bytes=[ec51555555550000]
[frame] frame_unwind_register_value: exit
[frame] frame_id_p: l={stack=<sentinel>,!code,special=0x0000000000000000} -> 1
[frame] frame_id_eq: l={stack=<sentinel>,!code,special=0x0000000000000000}, r={stack=<sentinel>,!code,special=0x0000000000000000} -> 1
[frame] get_prev_frame: enter
[frame] get_prev_frame_always_1: enter
[frame] get_prev_frame_always_1: this_frame=-1
[frame] get_prev_frame_always_1: -> {level=0,type=NORMAL_FRAME,unwind=0x5588ee3d1888,pc=0x5555555551ec,id=<not computed>,func=<unknown>} // cached
[frame] get_prev_frame_always_1: exit
[frame] get_prev_frame: exit
[frame] value_fetch_lazy_register: (frame=0, regnum=16(rip), ...) -> register=16 bytes=[ec51555555550000]
[py-unwind] pyuw_sniffer: frame claimed by unwinder test unwinder
[py-unwind] pyuw_sniffer: exit
[frame] frame_unwind_try_unwinder: yes
[frame] frame_unwind_find_by_frame: exit
gdb/ChangeLog:
* frame.h (FRAME_SCOPED_DEBUG_ENTER_EXIT): New.
* frame.c (compute_frame_id, get_prev_frame_always_1,
get_prev_frame): Use FRAME_SCOPED_DEBUG_ENTER_EXIT.
* frame-unwind.c (frame_unwind_find_by_frame): Likewise.
(frame_unwind_register_value): Likewise.
Change-Id: I45b69b4ed962e70572bc55b8adfb211483c1eeed
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Introduce frame_debug_printf, to convert the "frame" debug messages to
the new system. Replace fprint_frame with a frame_info::to_string
method that returns a string, like what was done with
frame_id::to_string. This makes it easier to use with
frame_debug_printf.
gdb/ChangeLog:
* frame.h (frame_debug_printf): New.
* frame.c: Use frame_debug_printf throughout when printing frame
debug messages.
* amd64-windows-tdep.c: Likewise.
* value.c: Likewise.
gdb/testsuite/ChangeLog:
* gdb.dwarf2/dw2-reg-undefined.exp: Update regexp.
Change-Id: I3c230b0814ea81c23af3e1aca1aac8d4ba91d726
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gdb/ChangeLog:
* frame.h (frame_debug): Change type to bool.
* frame.c (frame_debug): Change type to bool.
(_initialize_frame): Adjust.
Change-Id: I27b5359a25ad53ac42618b5708a025c348a1eeda
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Replace fprint_frame_id with a member function frame_id::to_string
that returns a std::string. Convert all of the previous users of
fprint_frame_id to use the new member function. This means that
instead of writing things like this:
fprintf_unfiltered (file, " id=");
fprint_frame_id (file, s->id.id);
We can write this:
fprintf_unfiltered (file, " id=%s", s->id.id.to_string ().c_str ());
There should be no user visible changes after this commit.
gdb/ChangeLog:
* dummy-frame.c (fprint_dummy_frames): Convert use of
fprint_frame_id to use frame_id::to_string.
* frame.c (fprint_field): Delete.
(fprint_frame_id): Moved to...
(frame_id::to_string): ...this, rewritten to return a string.
(fprint_frame): Convert use of fprint_frame_id to use
frame_id::to_string.
(compute_frame_id): Likewise.
(frame_id_p): Likewise.
(frame_id_eq): Likewise.
(frame_id_inner): Likewise.
* frame.h (struct frame_id) <to_string>: New member function.
(fprint_frame_id): Delete declaration.
* guile/scm-frame.c (frscm_print_frame_smob): Convert use of
fprint_frame_id to use frame_id::to_string.
* python/py-frame.c (frame_object_to_frame_info): Likewise.
* python/py-unwind.c (unwind_infopy_str): Likewise.
(pyuw_this_id): Likewise.
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This patch converts the most obvious functions from gdb/frame.h to use
the gdb::array_view abstraction. I've converted the ones that used buffer +
length.
There are others using only the buffer, with an implicit size. I did not
touch those for now. But it would be nice to pass the size for safety.
Tested with --enable-targets=all on Ubuntu 18.04/20.04 aarch64-linux.
gdb/ChangeLog
2021-01-19 Luis Machado <luis.machado@linaro.org>
* frame.h (get_frame_register_bytes): Pass a gdb::array_view instead
of buffer + length.
(put_frame_register_bytes): Likewise.
Adjust documentation.
(get_frame_memory): Pass a gdb::array_view instead of buffer + length.
(safe_frame_unwind_memory): Likewise.
* frame.c (get_frame_register_bytes, put_frame_register_bytes)
(get_frame_memory, safe_frame_unwind_memory): Adjust to use
gdb::array_view.
* amd64-fbsd-tdep.c (amd64fbsd_sigtramp_p): Likewise.
* amd64-linux-tdep.c (amd64_linux_sigtramp_start): Likewise.
* amd64-obsd-tdep.c (amd64obsd_sigtramp_p): Likewise.
* arc-linux-tdep.c (arc_linux_is_sigtramp): Likewise.
* cris-tdep.c (cris_sigtramp_start, cris_rt_sigtramp_start): Likewise.
* dwarf2/loc.c (rw_pieced_value): Likewise.
* hppa-tdep.c (hppa_frame_cache): Likewise.
* i386-fbsd-tdep.c (i386fbsd_sigtramp_p): Likewise.
* i386-gnu-tdep.c (i386_gnu_sigtramp_start): Likewise.
* i386-linux-tdep.c (i386_linux_sigtramp_start)
(i386_linux_rt_sigtramp_start): Likewise.
* i386-obsd-tdep.c (i386obsd_sigtramp_p): Likewise.
* i386-tdep.c (i386_register_to_value): Likewise.
* i387-tdep.c (i387_register_to_value): Likewise.
* ia64-tdep.c (ia64_register_to_value): Likewise.
* m32r-linux-tdep.c (m32r_linux_sigtramp_start)
(m32r_linux_rt_sigtramp_start): Likewise.
* m68k-linux-tdep.c (m68k_linux_pc_in_sigtramp): Likewise.
* m68k-tdep.c (m68k_register_to_value): Likewise.
* mips-tdep.c (mips_register_to_value)
(mips_value_to_register): Likewise.
* ppc-fbsd-tdep.c (ppcfbsd_sigtramp_frame_sniffer)
(ppcfbsd_sigtramp_frame_cache): Likewise.
* ppc-obsd-tdep.c (ppcobsd_sigtramp_frame_sniffer)
(ppcobsd_sigtramp_frame_cache): Likewise.
* rs6000-tdep.c (rs6000_in_function_epilogue_frame_p)
(rs6000_register_to_value): Likewise.
* tilegx-tdep.c (tilegx_analyze_prologue): Likewise.
* tramp-frame.c (tramp_frame_start): Likewise.
* valops.c (value_assign): Likewise.
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This commits the result of running gdb/copyright.py as per our Start
of New Year procedure...
gdb/ChangeLog
Update copyright year range in copyright header of all GDB files.
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gdb/ChangeLog:
* frame.c: Remove trailing white spaces.
* frame.h: Likewise.
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If the remote target closes while we're reading registers/memory for
restoring the selected frame in scoped_restore_current_thread's dtor,
the corresponding TARGET_CLOSE_ERROR error is swallowed by the
scoped_restore_current_thread's dtor, because letting exceptions
escape from a dtor is bad. It isn't great to lose that errors like
that, though. I've been thinking about how to avoid it, and I came up
with this patch.
The idea here is to make scoped_restore_current_thread's dtor do as
little as possible, to avoid any work that might throw in the first
place. And to do that, instead of having the dtor call
restore_selected_frame, which re-finds the previously selected frame,
just record the frame_id/level of the desired selected frame, and have
get_selected_frame find the frame the next time it is called. In
effect, this implements most of Cagney's suggestion, here:
/* On demand, create the selected frame and then return it. If the
selected frame can not be created, this function prints then throws
an error. When MESSAGE is non-NULL, use it for the error message,
otherwize use a generic error message. */
/* FIXME: cagney/2002-11-28: At present, when there is no selected
frame, this function always returns the current (inner most) frame.
It should instead, when a thread has previously had its frame
selected (but not resumed) and the frame cache invalidated, find
and then return that thread's previously selected frame. */
extern struct frame_info *get_selected_frame (const char *message);
The only thing missing to fully implement that would be to make
reinit_frame_cache just clear selected_frame instead of calling
select_frame(NULL), and the call select_frame(NULL) explicitly in the
places where we really wanted reinit_frame_cache to go back to the
current frame too. That can done separately, though, I'm not
proposing to do that in this patch.
Note that this patch renames restore_selected_frame to
lookup_selected_frame, and adds a new restore_selected_frame function
that doesn't throw, to be paired with the also-new save_selected_frame
function.
There's a restore_selected_frame function in infrun.c that I think can
be replaced by the new one in frame.c.
Also done in this patch is make the get_selected_frame's parameter be
optional, so that we don't have to pass down nullptr explicitly all
over the place.
lookup_selected_frame should really move from thread.c to frame.c, but
I didn't do that here, just to avoid churn in the patch while it
collects comments. I did make it extern and declared it in frame.h
already, preparing for the move. I will do the move as a follow up
patch if people agree with this approach.
Incidentally, this patch alone would fix the crashes fixed by the
previous patches in the series, because with this,
scoped_restore_current_thread's constructor doesn't throw either.
gdb/ChangeLog:
* blockframe.c (block_innermost_frame): Use get_selected_frame.
* frame.c
(scoped_restore_selected_frame::scoped_restore_selected_frame):
Use save_selected_frame. Save language as well.
(scoped_restore_selected_frame::~scoped_restore_selected_frame):
Use restore_selected_frame, and restore language as well.
(selected_frame_id, selected_frame_level): New.
(selected_frame): Update comments.
(save_selected_frame, restore_selected_frame): New.
(get_selected_frame): Use lookup_selected_frame.
(get_selected_frame_if_set): Delete.
(select_frame): Record selected_frame_level and selected_frame_id.
* frame.h (scoped_restore_selected_frame) <m_level, m_lang>: New
fields.
(get_selected_frame): Make 'message' parameter optional.
(get_selected_frame_if_set): Delete declaration.
(select_frame): Update comments.
(save_selected_frame, restore_selected_frame)
(lookup_selected_frame): Declare.
* gdbthread.h (scoped_restore_current_thread) <m_lang>: New field.
* infrun.c (struct infcall_control_state) <selected_frame_level>:
New field.
(save_infcall_control_state): Use save_selected_frame.
(restore_selected_frame): Delete.
(restore_infcall_control_state): Use restore_selected_frame.
* stack.c (select_frame_command_core, frame_command_core): Use
get_selected_frame.
* thread.c (restore_selected_frame): Rename to ...
(lookup_selected_frame): ... this and make extern. Select the
current frame if the frame level is -1.
(scoped_restore_current_thread::restore): Also restore the
language.
(scoped_restore_current_thread::~scoped_restore_current_thread):
Don't try/catch.
(scoped_restore_current_thread::scoped_restore_current_thread):
Save the language as well. Use save_selected_frame.
Change-Id: I73fd1cfc40d8513c28e5596383b7ecd8bcfe700f
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In the following patch, we'll need to easily differentiate the frame_id
of the outer frame (or the frame id of a frame inlined into the outer
frame) from a simply invalid frame id.
Currently, the frame id of the outer frame has `stack_status` set to
FID_STACK_INVALID plus special_addr_p set. A frame inlined into the
outer frame would also have `artificial_depth` set to greater than one.
That makes the job of differntiating the frame id of the outer frame (or a
frame inlined into the outer frame) cumbersome.
To make it easier, give the outer frame id its own frame_id_stack_status
enum value. outer_frame_id then becomes very similar to
sentinel_frame_id, another "special" frame id value.
In frame_id_p, we don't need a special case for the outer frame id, as
it's no long a special case of FID_STACK_INVALID. Same goes for
frame_id_eq.
So in the end, FID_STACK_OUTER isn't even used (except in
fprint_frame_id). But that's expected: all the times we wanted to
identify an outer frame was to differentiate it from an otherwise
invalid frame. Since their frame_id_stack_status value is different
now, that is done naturally.
gdb/ChangeLog:
* frame.h (enum frame_id_stack_status) <FID_STACK_OUTER>: New.
* frame.c (fprint_frame_id): Handle FID_STACK_OUTER.
(outer_frame_id): Use FID_STACK_OUTER instead of
FID_STACK_INVALID.
(frame_id_p): Don't check for outer_frame_id.
Change-Id: I654e7f936349debc4f04f7f684b15e71a0c37619
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Change instances of int variables and return values used as boolean
values to use the bool type.
Shorten the comments of a few functions, because I think they go a bit
too much in implementation details, which appear out of date anyway.
Make other misc changes to the functions that are already being changed,
such as using nullptr instead of NULL, dropping `struct` keywords and
declaring variables when first used.
gdb/ChangeLog:
* frame.h (frame_id_p): Return bool.
(frame_id_artificial_p): Return bool.
(frame_id_eq): Return bool.
(has_stack_frames): Return bool.
(get_selected_frame): Fix typo in comment.
(get_frame_pc_if_available): Return bool.
(get_frame_address_in_block_if_available): Return bool.
(get_frame_func_if_available): Return bool.
(read_frame_register_unsigned): Return bool.
(get_frame_register_bytes): Return bool.
(safe_frame_unwind_memory): Return bool.
(deprecated_frame_register_read): Return bool.
(frame_unwinder_is): Return bool.
* frame.c (struct frame_info) <prev_arch::p>: Change type to
bool.
<this_id::p>: Likewise.
<prev_p>: Likewise.
(frame_stash_add): Return bool.
(get_frame_id): Use bool.
(frame_id_build_special) Use bool.
(frame_id_build_unavailable_stack): Use bool.
(frame_id_build): Use bool.
(frame_id_p): Return bool, use true/false instead of 1/0.
(frame_id_artificial_p): Likewise.
(frame_id_eq): Likewise.
(frame_id_inner): Likewise.
(get_frame_func_if_available): Likewise.
(read_frame_register_unsigned): Likewise.
(deprecated_frame_register_read): Likewise.
(get_frame_register_bytes): Likewise.
(has_stack_frames): Likewise.
(inside_main_func): Likewise.
(inside_entry_func): Likewise.
(get_frame_pc_if_available): Likewise.
(get_frame_address_in_block_if_available): Likewise.
(frame_unwinder_is): Likewise.
(safe_frame_unwind_memory): Likewise.
(frame_unwind_arch): Likewise.
Change-Id: I6121fa56739b688be79d73d087d76b268ba5a46a
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This fixes yet another bug exposed by ASAN + multi-target.exp
Running an Asan-enabled GDB against gdb.multi/multi-target.exp exposed
yet another latent GDB bug. See here for the full log:
https://sourceware.org/pipermail/gdb-patches/2020-July/170761.html
As Simon described, the problem is:
- We create a new frame_info object in restore_selected_frame (by
calling find_relative_frame)
- The frame is allocated on the frame_cache_obstack
- In frame_unwind_try_unwinder, we try to find an unwinder for that
frame
- While trying unwinders, memory read fails because the remote target
closes, because of "monitor exit"
- That calls reinit_frame_cache (as shown above), which resets
frame_cache_obstack
- When handling the exception in frame_unwind_try_unwinder, we try to
set some things on the frame_info object (like *this_cache, which
in fact tries to write into frame_info::prologue_cache), but the
frame_info object is no more, it went away with the obstack.
Fix this by maintaining a frame cache generation counter. Then in
exception handling code paths, don't touch frame objects if the
generation is not the same as it was on entry.
This commit generalizes the gdb.server/server-kill.exp testcase and
reuses it to test the scenario in question. The new tests fail
without the GDB fix.
gdb/ChangeLog:
* frame-unwind.c (frame_unwind_try_unwinder): On exception, don't
touch THIS_CACHE/THIS_FRAME if the frame cache was cleared
meanwhile.
* frame.c (frame_cache_generation, get_frame_cache_generation):
New.
(reinit_frame_cache): Increment FRAME_CACHE_GENERATION.
(get_prev_frame_if_no_cycle): On exception, don't touch
PREV_FRAME/THIS_FRAME if the frame cache was cleared meanwhile.
* frame.h (get_frame_cache_generation): Declare.
gdb/testsuite/ChangeLog:
* gdb.server/server-kill.exp (prepare): New, factored out from the
top level.
(kill_server): New.
(test_tstatus, test_unwind_nosyms, test_unwind_syms): New.
(top level) : Call test_tstatus, test_unwind_nosyms, test_unwind_syms.
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This started with me running into the bug described in python/22748,
in summary, if the frame sniffing code accessed any registers within
an inline frame then GDB would crash with this error:
gdb/frame.c:579: internal-error: frame_id get_frame_id(frame_info*): Assertion `fi->level == 0' failed.
The problem is that, when in the Python unwinder I write this:
pending_frame.read_register ("register-name")
This is translated internally into a call to `value_of_register',
which in turn becomes a call to `value_of_register_lazy'.
Usually this isn't a problem, `value_of_register_lazy' requires the
next frame (more inner) to have a valid frame_id, which will be the
case (if we're sniffing frame #1, then frame #0 will have had its
frame-id figured out).
Unfortunately if frame #0 is inline within frame #1, then the frame-id
for frame #0 can't be computed until we have the frame-id for #1. As
a result we can't create a lazy register for frame #1 when frame #0 is
inline.
Initially I proposed a solution inline with that proposed in bugzilla,
changing value_of_register to avoid creating a lazy register value.
However, when this was discussed on the mailing list I got this reply:
https://sourceware.org/pipermail/gdb-patches/2020-June/169633.html
Which led me to look at these two patches:
[1] https://sourceware.org/pipermail/gdb-patches/2020-April/167612.html
[2] https://sourceware.org/pipermail/gdb-patches/2020-April/167930.html
When I considered patches [1] and [2] I saw that all of the issues
being addressed here were related, and that there was a single
solution that could address all of these issues.
First I wrote the new test gdb.opt/inline-frame-tailcall.exp, which
shows that [1] and [2] regress the inline tail-call unwinder, the
reason for this is that these two patches replace a call to
gdbarch_unwind_pc with a call to get_frame_register, however, this is
not correct. The previous call to gdbarch_unwind_pc takes THIS_FRAME
and returns the $pc value in the previous frame. In contrast
get_frame_register takes THIS_FRAME and returns the value of the $pc
in THIS_FRAME; these calls are not equivalent.
The reason these patches appear (or do) fix the regressions listed in
[1] is that the tail call sniffer depends on identifying the address
of a caller and a callee, GDB then looks for a tail-call sequence that
takes us from the caller address to the callee, if such a series is
found then tail-call frames are added.
The bug that was being hit, and which was address in patch [1] is that
in order to find the address of the caller, GDB ended up creating a
lazy register value for an inline frame with to frame-id. The
solution in patch [1] is to instead take the address of the callee and
treat this as the address of the caller. Getting the address of the
callee works, but we then end up looking for a tail-call series from
the callee to the callee, which obviously doesn't return any sane
results, so we don't insert any tail call frames.
The original patch [1] did cause some breakage, so patch [2] undid
patch [1] in all cases except those where we had an inline frame with
no frame-id. It just so happens that there were no tests that fitted
this description _and_ which required tail-call frames to be
successfully spotted, as a result patch [2] appeared to work.
The new test inline-frame-tailcall.exp, exposes the flaw in patch [2].
This commit undoes patch [1] and [2], and replaces them with a new
solution, which is also different to the solution proposed in the
python/22748 bug report.
In this solution I propose that we introduce some special case logic
to value_of_register_lazy. To understand what this logic is we must
first look at how inline frames unwind registers, this is very simple,
they do this:
static struct value *
inline_frame_prev_register (struct frame_info *this_frame,
void **this_cache, int regnum)
{
return get_frame_register_value (this_frame, regnum);
}
And remember:
struct value *
get_frame_register_value (struct frame_info *frame, int regnum)
{
return frame_unwind_register_value (frame->next, regnum);
}
So in all cases, unwinding a register in an inline frame just asks the
next frame to unwind the register, this makes sense, as an inline
frame doesn't really exist, when we unwind a register in an inline
frame, we're really just asking the next frame for the value of the
register in the previous, non-inline frame.
So, if we assume that we only get into the missing frame-id situation
when we try to unwind a register from an inline frame during the frame
sniffing process, then we can change value_of_register_lazy to not
create lazy register values for an inline frame.
Imagine this stack setup, where #1 is inline within #2.
#3 -> #2 -> #1 -> #0
\______/
inline
Now when trying to figure out the frame-id for #1, we need to compute
the frame-id for #2. If the frame sniffer for #2 causes a lazy
register read in #2, either due to a Python Unwinder, or for the
tail-call sniffer, then we call value_of_register_lazy passing in
frame #2.
In value_of_register_lazy, we grab the next frame, which is #1, and we
used to then ask for the frame-id of #1, which was not computed, and
this was our bug.
Now, I propose we spot that #1 is an inline frame, and so lookup the
next frame of #1, which is #0. As #0 is not inline it will have a
valid frame-id, and so we create a lazy register value using #0 as the
next-frame-id. This will give us the exact same result we had
previously (thanks to the code we inspected above).
Encoding into value_of_register_lazy the knowledge that reading an
inline frame register will always just forward to the next frame
feels.... not ideal, but this seems like the cleanest solution to this
recursive frame-id computation/sniffing issue that appears to crop
up.
The following two commits are fully reverted with this commit, these
correspond to patches [1] and [2] respectively:
commit 5939967b355ba6a940887d19847b7893a4506067
Date: Tue Apr 14 17:26:22 2020 -0300
Fix inline frame unwinding breakage
commit 991a3e2e9944a4b3a27bd989ac03c18285bd545d
Date: Sat Apr 25 00:32:44 2020 -0300
Fix remaining inline/tailcall unwinding breakage for x86_64
gdb/ChangeLog:
PR python/22748
* dwarf2/frame-tailcall.c (dwarf2_tailcall_sniffer_first): Remove
special handling for inline frames.
* findvar.c (value_of_register_lazy): Skip inline frames when
creating lazy register values.
* frame.c (frame_id_computed_p): Delete definition.
* frame.h (frame_id_computed_p): Delete declaration.
gdb/testsuite/ChangeLog:
PR python/22748
* gdb.opt/inline-frame-tailcall.c: New file.
* gdb.opt/inline-frame-tailcall.exp: New file.
* gdb.python/py-unwind-inline.c: New file.
* gdb.python/py-unwind-inline.exp: New file.
* gdb.python/py-unwind-inline.py: New file.
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|
Commit 5939967b355ba6a940887d19847b7893a4506067 fixed inline
frame unwinding breakage for some targets (aarch64, riscv, s390...)
but regressed a few amd64 testcases related to tailcalls.
Given the following example situation...
Frame #-1 - sentinel frame
Frame # 0 - inline frame
Frame # 1 - normal frame
... suppose we're at level #1 and call into dwarf2_tailcall_sniffer_first.
We'll attempt to fetch PC, which used to be done via the gdbarch_unwind_pc call
(before 5939967b355ba6a940887d19847b7893a4506067), but now it is being handled
by the get_frame_register function.
gdbarch_unwind_pc will attempt to use frame #1's cache to retrieve information
about the PC. Here's where different architectures behave differently.
x86_64 will find a dwarf rule to retrieve PC from memory, at a CFA + offset
location. So the PC value is readily available and there is no need to
create a lazy value.
For aarch64 (and others), GCC doesn't emit an explicit location for PC, so we
eventually will find that PC is DWARF2_FRAME_REG_UNSPECIFIED. This is known
and is handled by GDB by assuming GCC really meant DWARF2_FRAME_REG_SAME_VALUE.
This means we'll attempt to fetch the register value from frame #0, via a call
to frame_unwind_got_register, which will trigger the creation of a lazy value
that requires a valid frame id for frame #0.
We don't have a valid id for frame #0 yet, so we assert.
Given the above, the following patch attempts to handle the situation without
being too hacky. We verify if the next frame is an inline frame and if its
frame id has been computed already. If it hasn't been computed yet, then we
use the safer get_frame_register function, otherwise we use the regular
gdbarch_unwind_pc hook.
gdb/ChangeLog:
2020-04-27 Luis Machado <luis.machado@linaro.org>
* dwarf2/frame-tailcall.c (dwarf2_tailcall_sniffer_first): Handle
problematic inline frame unwinding situation.
* frame.c (frame_id_computed_p): New function.
* frame.h (frame_id_computed_p): New prototype.
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|
gdb/ChangeLog:
Update copyright year range in all GDB files.
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|
Fix typos in comments. NFC.
Tested on x86_64-linux.
gdb/ChangeLog:
2019-10-26 Tom de Vries <tdevries@suse.de>
* aarch64-linux-tdep.c: Fix typos in comments.
* aarch64-tdep.c: Same.
* ada-lang.c: Same.
* amd64-nat.c: Same.
* arc-tdep.c: Same.
* arch/aarch64-insn.c: Same.
* block.c: Same.
* breakpoint.h: Same.
* btrace.h: Same.
* c-varobj.c: Same.
* cli/cli-decode.c: Same.
* cli/cli-script.c: Same.
* cli/cli-utils.h: Same.
* coff-pe-read.c: Same.
* coffread.c: Same.
* compile/compile-cplus-symbols.c: Same.
* compile/compile-object-run.c: Same.
* completer.c: Same.
* corelow.c: Same.
* cp-support.c: Same.
* demangle.c: Same.
* dwarf-index-write.c: Same.
* dwarf2-frame.c: Same.
* dwarf2-frame.h: Same.
* eval.c: Same.
* frame-base.h: Same.
* frame.h: Same.
* gdbcmd.h: Same.
* gdbtypes.h: Same.
* gnu-nat.c: Same.
* guile/scm-objfile.c: Same.
* i386-tdep.c: Same.
* i386-tdep.h: Same.
* infcall.c: Same.
* infcall.h: Same.
* linux-nat.c: Same.
* m68k-tdep.c: Same.
* macroexp.c: Same.
* memattr.c: Same.
* mi/mi-cmd-disas.c: Same.
* mi/mi-getopt.h: Same.
* mi/mi-main.c: Same.
* minsyms.c: Same.
* nat/aarch64-sve-linux-sigcontext.h: Same.
* objfiles.h: Same.
* ppc-linux-nat.c: Same.
* ppc-linux-tdep.c: Same.
* ppc-tdep.h: Same.
* progspace.h: Same.
* prologue-value.h: Same.
* python/py-evtregistry.c: Same.
* python/py-instruction.h: Same.
* record-btrace.c: Same.
* record-full.c: Same.
* remote.c: Same.
* rs6000-tdep.c: Same.
* ser-tcp.c: Same.
* sol-thread.c: Same.
* sparc-sol2-tdep.c: Same.
* sparc64-tdep.c: Same.
* stabsread.c: Same.
* symfile.c: Same.
* symtab.h: Same.
* target.c: Same.
* tracepoint.c: Same.
* tui/tui-data.h: Same.
* tui/tui-io.c: Same.
* tui/tui-win.c: Same.
* tui/tui.c: Same.
* unittests/rsp-low-selftests.c: Same.
* user-regs.h: Same.
* utils.c: Same.
* utils.h: Same.
* valarith.c: Same.
* valops.c: Same.
* valprint.c: Same.
* valprint.h: Same.
* value.c: Same.
* value.h: Same.
* varobj.c: Same.
* x86-nat.h: Same.
* xtensa-tdep.c: Same.
gdb/gdbserver/ChangeLog:
2019-10-26 Tom de Vries <tdevries@suse.de>
* linux-aarch64-low.c: Fix typos in comments.
* linux-arm-low.c: Same.
* linux-low.c: Same.
* linux-ppc-low.c: Same.
* proc-service.c: Same.
* regcache.h: Same.
* server.c: Same.
* tracepoint.c: Same.
* win32-low.c: Same.
gdb/stubs/ChangeLog:
2019-10-26 Tom de Vries <tdevries@suse.de>
* ia64vms-stub.c: Fix typos in comments.
* m32r-stub.c: Same.
* m68k-stub.c: Same.
* sh-stub.c: Same.
gdb/testsuite/ChangeLog:
2019-10-26 Tom de Vries <tdevries@suse.de>
* gdb.base/bigcore.c: Fix typos in comments.
* gdb.base/ctf-ptype.c: Same.
* gdb.base/long_long.c: Same.
* gdb.dwarf2/dw2-op-out-param.S: Same.
* gdb.python/py-evthreads.c: Same.
* gdb.reverse/i387-stack-reverse.c: Same.
* gdb.trace/tfile.c: Same.
* lib/compiler.c: Same.
* lib/compiler.cc: Same.
Change-Id: I8573d84a577894270179ae30f46c48d806fc1beb
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|
This is for add_setshow_boolean_cmd as well as the gdb::option interface.
gdb/ChangeLog:
2019-09-17 Christian Biesinger <cbiesinger@google.com>
* ada-lang.c (ada_ignore_descriptive_types_p): Change to bool.
(print_signatures): Likewise.
(trust_pad_over_xvs): Likewise.
* arch/aarch64-insn.c (aarch64_debug): Likewise.
* arch/aarch64-insn.h (aarch64_debug): Likewise.
* arm-linux-nat.c (arm_apcs_32): Likewise.
* arm-linux-tdep.c (arm_apcs_32): Likewise.
* arm-nbsd-nat.c (arm_apcs_32): Likewise.
* arm-tdep.c (arm_debug): Likewise.
(arm_apcs_32): Likewise.
* auto-load.c (debug_auto_load): Likewise.
(auto_load_gdb_scripts): Likewise.
(global_auto_load): Likewise.
(auto_load_local_gdbinit): Likewise.
(auto_load_local_gdbinit_loaded): Likewise.
* auto-load.h (global_auto_load): Likewise.
(auto_load_local_gdbinit): Likewise.
(auto_load_local_gdbinit_loaded): Likewise.
* breakpoint.c (disconnected_dprintf): Likewise.
(breakpoint_proceeded): Likewise.
(automatic_hardware_breakpoints): Likewise.
(always_inserted_mode): Likewise.
(target_exact_watchpoints): Likewise.
(_initialize_breakpoint): Update.
* breakpoint.h (target_exact_watchpoints): Change to bool.
* btrace.c (maint_btrace_pt_skip_pad): Likewise.
* cli/cli-cmds.c (trace_commands): Likewise.
* cli/cli-cmds.h (trace_commands): Likewise.
* cli/cli-decode.c (add_setshow_boolean_cmd): Change int* argument
to bool*.
* cli/cli-logging.c (logging_overwrite): Change to bool.
(logging_redirect): Likewise.
(debug_redirect): Likewise.
* cli/cli-option.h (option_def) <boolean>: Change return type to bool*.
(struct boolean_option_def) <get_var_address_cb_>: Change return type
to bool.
<boolean_option_def>: Update.
(struct flag_option_def): Change default type of Context to bool
from int.
<flag_option_def>: Change return type of var_address_cb_ to bool*.
* cli/cli-setshow.c (do_set_command): Cast to bool* instead of int*.
(get_setshow_command_value_string): Likewise.
* cli/cli-style.c (cli_styling): Change to bool.
(source_styling): Likewise.
* cli/cli-style.h (source_styling): Likewise.
(cli_styling): Likewise.
* cli/cli-utils.h (struct qcs_flags) <quiet, cont, silent>: Change
to bool.
* command.h (var_types): Update comment.
(add_setshow_boolean_cmd): Change int* var argument to bool*.
* compile/compile-cplus-types.c (debug_compile_cplus_types): Change to
bool.
(debug_compile_cplus_scopes): Likewise.
* compile/compile-internal.h (compile_debug): Likewise.
* compile/compile.c (compile_debug): Likewise.
(struct compile_options) <raw>: Likewise.
* cp-support.c (catch_demangler_crashes): Likewise.
* cris-tdep.c (usr_cmd_cris_version_valid): Likewise.
(usr_cmd_cris_dwarf2_cfi): Likewise.
* csky-tdep.c (csky_debug): Likewise.
* darwin-nat.c (enable_mach_exceptions): Likewise.
* dcache.c (dcache_enabled_p): Likewise.
* defs.h (info_verbose): Likewise.
* demangle.c (demangle): Likewise.
(asm_demangle): Likewise.
* dwarf-index-cache.c (debug_index_cache): Likewise.
* dwarf2-frame.c (dwarf2_frame_unwinders_enabled_p): Likewise.
* dwarf2-frame.h (dwarf2_frame_unwinders_enabled_p): Likewise.
* dwarf2read.c (check_physname): Likewise.
(use_deprecated_index_sections): Likewise.
(dwarf_always_disassemble): Likewise.
* eval.c (overload_resolution): Likewise.
* event-top.c (set_editing_cmd_var): Likewise.
(exec_done_display_p): Likewise.
* event-top.h (set_editing_cmd_var): Likewise.
(exec_done_display_p): Likewise.
* exec.c (write_files): Likewise.
* fbsd-nat.c (debug_fbsd_lwp): Likewise
(debug_fbsd_nat): Likewise.
* frame.h (struct frame_print_options) <print_raw_frame_arguments>:
Likewise.
(struct set_backtrace_options) <backtrace_past_main>: Likewise.
<backtrace_past_entry> Likewise.
* gdb-demangle.h (demangle): Likewise.
(asm_demangle): Likewise.
* gdb_bfd.c (bfd_sharing): Likewise.
* gdbcore.h (write_files): Likewise.
* gdbsupport/common-debug.c (show_debug_regs): Likewise.
* gdbsupport/common-debug.h (show_debug_regs): Likewise.
* gdbthread.h (print_thread_events): Likewise.
* gdbtypes.c (opaque_type_resolution): Likewise.
(strict_type_checking): Likewise.
* gnu-nat.c (gnu_debug_flag): Likewise.
* guile/scm-auto-load.c (auto_load_guile_scripts): Likewise.
* guile/scm-param.c (pascm_variable): Add boolval.
(add_setshow_generic): Update.
(pascm_param_value): Update.
(pascm_set_param_value_x): Update.
* hppa-tdep.c (hppa_debug): Change to bool..
* infcall.c (may_call_functions_p): Likewise.
(coerce_float_to_double_p): Likewise.
(unwind_on_signal_p): Likewise.
(unwind_on_terminating_exception_p): Likewise.
* infcmd.c (startup_with_shell): Likewise.
* inferior.c (print_inferior_events): Likewise.
* inferior.h (startup_with_shell): Likewise.
(print_inferior_events): Likewise.
* infrun.c (step_stop_if_no_debug): Likewise.
(detach_fork): Likewise.
(debug_displaced): Likewise.
(disable_randomization): Likewise.
(non_stop): Likewise.
(non_stop_1): Likewise.
(observer_mode): Likewise.
(observer_mode_1): Likewise.
(set_observer_mode): Update.
(sched_multi): Change to bool.
* infrun.h (debug_displaced): Likewise.
(sched_multi): Likewise.
(step_stop_if_no_debug): Likewise.
(non_stop): Likewise.
(disable_randomization): Likewise.
* linux-tdep.c (use_coredump_filter): Likewise.
(dump_excluded_mappings): Likewise.
* linux-thread-db.c (auto_load_thread_db): Likewise.
(check_thread_db_on_load): Likewise.
* main.c (captured_main_1): Update.
* maint-test-options.c (struct test_options_opts) <flag_opt, xx1_opt,
xx2_opt, boolean_opt>: Change to bool.
* maint-test-settings.c (maintenance_test_settings_boolean): Likewise.
* maint.c (maintenance_profile_p): Likewise.
(per_command_time): Likewise.
(per_command_space): Likewise.
(per_command_symtab): Likewise.
* memattr.c (inaccessible_by_default): Likewise.
* mi/mi-main.c (mi_async): Likewise.
(mi_async_1): Likewise.
* mips-tdep.c (mips64_transfers_32bit_regs_p): Likewise.
* nat/fork-inferior.h (startup_with_shell): Likewise.
* nat/linux-namespaces.c (debug_linux_namespaces): Likewise.
* nat/linux-namespaces.h (debug_linux_namespaces): Likewise.
* nios2-tdep.c (nios2_debug): Likewise.
* or1k-tdep.c (or1k_debug): Likewise.
* parse.c (parser_debug): Likewise.
* parser-defs.h (parser_debug): Likewise.
* printcmd.c (print_symbol_filename): Likewise.
* proc-api.c (procfs_trace): Likewise.
* python/py-auto-load.c (auto_load_python_scripts): Likewise.
* python/py-param.c (union parmpy_variable): Add "bool boolval" field.
(set_parameter_value): Update.
(add_setshow_generic): Update.
* python/py-value.c (copy_py_bool_obj): Change argument from int*
to bool*.
* python/python.c (gdbpy_parameter_value): Cast to bool* instead of
int*.
* ravenscar-thread.c (ravenscar_task_support): Change to bool.
* record-btrace.c (record_btrace_target::store_registers): Update.
* record-full.c (record_full_memory_query): Change to bool.
(record_full_stop_at_limit): Likewise.
* record-full.h (record_full_memory_query): Likewise.
* remote-notif.c (notif_debug): Likewise.
* remote-notif.h (notif_debug): Likewise.
* remote.c (use_range_stepping): Likewise.
(interrupt_on_connect): Likewise.
(remote_break): Likewise.
* ser-tcp.c (tcp_auto_retry): Likewise.
* ser-unix.c (serial_hwflow): Likewise.
* skip.c (debug_skip): Likewise.
* solib-aix.c (solib_aix_debug): Likewise.
* spu-tdep.c (spu_stop_on_load_p): Likewise.
(spu_auto_flush_cache_p): Likewise.
* stack.c (struct backtrace_cmd_options) <full, no_filters, hide>:
Likewise.
(struct info_print_options) <quiet>: Likewise.
* symfile-debug.c (debug_symfile): Likewise.
* symfile.c (auto_solib_add): Likewise.
(separate_debug_file_debug): Likewise.
* symfile.h (auto_solib_add): Likewise.
(separate_debug_file_debug): Likewise.
* symtab.c (basenames_may_differ): Likewise.
(struct filename_partial_match_opts) <dirname, basename>: Likewise.
(struct info_print_options) <quiet, exclude_minsyms>: Likewise.
(struct info_types_options) <quiet>: Likewise.
* symtab.h (demangle): Likewise.
(basenames_may_differ): Likewise.
* target-dcache.c (stack_cache_enabled_1): Likewise.
(code_cache_enabled_1): Likewise.
* target.c (trust_readonly): Likewise.
(may_write_registers): Likewise.
(may_write_memory): Likewise.
(may_insert_breakpoints): Likewise.
(may_insert_tracepoints): Likewise.
(may_insert_fast_tracepoints): Likewise.
(may_stop): Likewise.
(auto_connect_native_target): Likewise.
(target_stop_and_wait): Update.
(target_async_permitted): Change to bool.
(target_async_permitted_1): Likewise.
(may_write_registers_1): Likewise.
(may_write_memory_1): Likewise.
(may_insert_breakpoints_1): Likewise.
(may_insert_tracepoints_1): Likewise.
(may_insert_fast_tracepoints_1): Likewise.
(may_stop_1): Likewise.
* target.h (target_async_permitted): Likewise.
(may_write_registers): Likewise.
(may_write_memory): Likewise.
(may_insert_breakpoints): Likewise.
(may_insert_tracepoints): Likewise.
(may_insert_fast_tracepoints): Likewise.
(may_stop): Likewise.
* thread.c (struct info_threads_opts) <show_global_ids>: Likewise.
(make_thread_apply_all_options_def_group): Change argument from int*
to bool*.
(thread_apply_all_command): Update.
(print_thread_events): Change to bool.
* top.c (confirm): Likewise.
(command_editing_p): Likewise.
(history_expansion_p): Likewise.
(write_history_p): Likewise.
(info_verbose): Likewise.
* top.h (confirm): Likewise.
(history_expansion_p): Likewise.
* tracepoint.c (disconnected_tracing): Likewise.
(circular_trace_buffer): Likewise.
* typeprint.c (print_methods): Likewise.
(print_typedefs): Likewise.
* utils.c (debug_timestamp): Likewise.
(sevenbit_strings): Likewise.
(pagination_enabled): Likewise.
* utils.h (sevenbit_strings): Likewise.
(pagination_enabled): Likewise.
* valops.c (overload_resolution): Likewise.
* valprint.h (struct value_print_options) <prettyformat_arrays,
prettyformat_structs, vtblprint, unionprint, addressprint, objectprint,
stop_print_at_null, print_array_indexes, deref_ref, static_field_print,
pascal_static_field_print, raw, summary, symbol_print, finish_print>:
Likewise.
* windows-nat.c (new_console): Likewise.
(cygwin_exceptions): Likewise.
(new_group): Likewise.
(debug_exec): Likewise.
(debug_events): Likewise.
(debug_memory): Likewise.
(debug_exceptions): Likewise.
(useshell): Likewise.
* windows-tdep.c (maint_display_all_tib): Likewise.
* xml-support.c (debug_xml): Likewise.
|
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This changes struct frame_arg to be self-managing and then fixes the
various users.
Tested by the buildbot.
gdb/ChangeLog
2019-08-07 Tom Tromey <tromey@adacore.com>
* stack.c (print_frame_arg, read_frame_local, read_frame_arg)
(print_frame_args): Update.
* python/py-framefilter.c (py_print_single_arg, enumerate_args):
Update.
* mi/mi-cmd-stack.c (list_arg_or_local): Update.
* frame.h (struct frame_arg): Add initializers.
<error>: Now a unique_xmalloc_ptr.
|
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Armv8.3-a Pointer Authentication causes the function return address to be
obfuscated on entry to some functions. GDB must unmask the link register in
order to produce a backtrace.
The following patch adds markers of [PAC] to the bracktrace, to indicate
which addresses needed unmasking. This includes the backtrace when using MI.
For example, consider the following backtrace:
(gdb) bt
0 0x0000000000400490 in puts@plt ()
1 0x00000000004005dc in foo ("hello") at cbreak-lib.c:6
2 0x0000000000400604 [PAC] in bar () at cbreak-lib.c:12
3 0x0000000000400620 [PAC] in main2 () at cbreak.c:17
4 0x00000000004005b4 in main () at cbreak-3.c:10
The functions in cbreak-lib use pointer auth, which masks the return address
to the previous function, causing the addresses of bar (in the library) and main2
(in the main binary) to require unmasking in order to unwind the backtrace.
An extra bool is added alongside the prev_pc in the frame structure. At the
point at which the link register is unmasked, the AArch64 port calls into frame
to sets the bool. This is the most efficient way of doing it.
The marker is also added to the python frame printer, which is always printed if
set. The marker is not explicitly exposed to the python code.
I expect this will potentially cause issues with some tests in the testsuite
when Armv8.3 pointer authentication is used. This should be fixed up in the
the future once real hardware is available for full testsuite testing.
gdb/ChangeLog:
* NEWS: Expand the Pointer Authentication entry.
* aarch64-tdep.c (aarch64_frame_unmask_address): Rename from this.
(aarch64_frame_unmask_lr): ... to this.
(aarch64_prologue_prev_register, aarch64_dwarf2_prev_register):
Call aarch64_frame_unmask_lr.
* frame.c (struct frame_info): Add "masked" variable.
(frame_set_previous_pc_masked) (frame_get_pc_masked): New functions.
(fprint_frame): Check for masked pc.
* frame.h (frame_set_previous_pc_masked) (frame_get_pc_masked): New
declarations.
* python/py-framefilter.c (py_print_frame): Check for masked pc.
* stack.c (print_frame): Check for masked pc.
gdb/doc/ChangeLog:
* gdb.texinfo (AArch64 Pointer Authentication): New subsection.
|
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New settings allow to better control what frame information is printed.
'set print frame-info' allows to override the default frame information
printed when a GDB command prints a frame.
The backtrace command has a new option -frame-info to override
this global setting.
It is now possible to have very short frame information by using the
new 'set print frame-arguments presence' and
'set print frame-info short-location'.
Combined with 'set print address off', a backtrace will only show
the essential information to see the function call chain, e.g.:
(gdb) set print address off
(gdb) set print frame-arguments presence
(gdb) set print frame-info short-location
(gdb) bt
#0 break_me ()
#1 call_me (...)
#2 main ()
(gdb)
This is handy in particular for big backtraces with functions having
many arguments.
Python frame filter printing logic has been updated to respect the new
setting in non MI mode.
Also, the default frame information printed was inconsistent when
backtrace was printing the frame information itself, or when the python
frame filtering code was printing the frame information.
This patch changes the default of python frame filtering to have a
consistent behaviour regarding printed frame-information, whatever
the presence/activity/matches of python filters.
2019-07-29 Philippe Waroquiers <philippe.waroquiers@skynet.be>
* frame.h (enum print_what): New value 'SHORT_LOCATION', update
comments.
(print_frame_info_auto, print_frame_info_source_line,
print_frame_info_location, print_frame_info_source_and_location,
print_frame_info_location_and_address, print_frame_info_short_location):
New declarations.
(struct frame_print_options): New member print_frame_info.
* extension.h (enum ext_lang_frame_args): New value CLI_PRESENCE.
* stack.h (get_user_print_what_frame_info): New declaration.
(frame_show_address): New declaration.
* stack.c (print_frame_arguments_choices): New value 'presence'.
(print_frame_info_auto, print_frame_info_source_line,
print_frame_info_location, print_frame_info_source_and_location,
print_frame_info_location_and_address, print_frame_info_short_location,
print_frame_info_choices, print_frame_info_print_what): New definitions.
(print_frame_args): Only print dots for args if print frame-arguments
is 'presence'.
(frame_print_option_defs): New element for "frame-info".
(get_user_print_what_frame_info): New function.
(frame_show_address): Make non static. Move comment to stack.h.
(print_frame_info_to_print_what): New function.
(print_frame_info): Update comment. Use fp_opts.print_frame_info
to decide what to print.
(backtrace_command_1): Handle the new print_frame_arguments_presence
value.
(_initialize_stack): Call add_setshow_enum_cmd for frame-info.
* python/py-framefilter.c (py_print_args): Handle CLI_PRESENCE.
(py_print_frame): In non-mi mode, use LOCATION as default for
print_what, similarly to frame information printed directly by
backtrace command. Handle frame-info user option in non MI mode.
|
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This adds support for comand options to the "backtrace" command. We'll get:
(gdb) bt -
-entry-values -hide -past-main
-frame-arguments -no-filters -raw-frame-arguments
-full -past-entry
~~~~
(gdb) help backtrace
Print backtrace of all stack frames, or innermost COUNT frames.
Usage: backtrace [OPTION]... [QUALIFIER]... [COUNT | -COUNT]
Options:
-entry-values no|only|preferred|if-needed|both|compact|default
Set printing of function arguments at function entry
GDB can sometimes determine the values of function arguments at entry,
in addition to their current values. This option tells GDB whether
to print the current value, the value at entry (marked as val@entry),
or both. Note that one or both of these values may be <optimized out>.
-frame-arguments all|scalars|none
Set printing of non-scalar frame arguments
-raw-frame-arguments [on|off]
Set whether to print frame arguments in raw form.
If set, frame arguments are printed in raw form, bypassing any
pretty-printers for that value.
-past-main [on|off]
Set whether backtraces should continue past "main".
Normally the caller of "main" is not of interest, so GDB will terminate
the backtrace at "main". Set this if you need to see the rest
of the stack trace.
-past-entry [on|off]
Set whether backtraces should continue past the entry point of a program.
Normally there are no callers beyond the entry point of a program, so GDB
will terminate the backtrace there. Set this if you need to see
the rest of the stack trace.
-full
Print values of local variables.
-no-filters
Prohibit frame filters from executing on a backtrace.
-hide
Causes Python frame filter elided frames to not be printed.
For backward compatibility, the following qualifiers are supported:
full - same as -full option.
no-filters - same as -no-filters option.
hide - same as -hide.
With a negative COUNT, print outermost -COUNT frames.
~~~~
Implementation wise, this:
- Moves relevant options/settings globals to structures.
- Tweaks a number of functions to pass down references to such structures.
- Adds option_def structures describing the options/settings.
- Makes backtrace_command parse the options, with gdb::option::process_options.
- Tweaks "backtrace"'s help to describe the new options.
- Adds testcases.
Note that backtrace is a PROCESS_OPTIONS_UNKNOWN_IS_OPERAND command,
because of the "-COUNT" argument.
The COUNT/-COUNT argument is currently parsed as an expression. I
considered whether it would be prudent here to require "--", but
concluded that the risk of causing a significant breakage here is much
lower compared to "print", since printing the expression is not the
whole point of the "backtrace" command. Seems OK to me to require
typing "backtrace -past-main -- -p" if the user truly wants to refer
to the negative of a backtrace count stored in an inferior variable
called "p".
gdb/ChangeLog:
2019-06-13 Pedro Alves <palves@redhat.com>
* frame.c: Include "cli/cli-option.h.
(user_set_backtrace_options): New.
(backtrace_past_main, backtrace_past_entry, backtrace_limit):
Delete.
(get_prev_frame): Adjust.
(boolean_option_def, uinteger_option_def)
(set_backtrace_option_defs): New.
(_initialize_frame): Adjust and use
gdb::option::add_setshow_cmds_for_options to install "set
backtrace past-main" and "set backtrace past-entry".
* frame.h: Include "cli/cli-option.h".
(struct frame_print_options): Forward declare.
(print_frame_arguments_all, print_frame_arguments_scalars)
(print_frame_arguments_none): Declare.
(print_entry_values): Delete declaration.
(struct frame_print_options, user_frame_print_options): New.
(struct set_backtrace_options): New.
(set_backtrace_option_defs, user_set_backtrace_options): Declare.
* mi/mi-cmd-stack.c (mi_cmd_stack_list_frames)
(mi_cmd_stack_list_locals, mi_cmd_stack_list_args)
(mi_cmd_stack_list_variables): Pass down USER_FRAME_PRINT_OPTIONS.
(list_args_or_locals): Add frame_print_options parameter.
(mi_cmd_stack_info_frame): Pass down USER_FRAME_PRINT_OPTIONS.
* python/py-framefilter.c (enumerate_args): Pass down
USER_FRAME_PRINT_OPTIONS.
* stack.c: Include "cli/cli-option.h".
(print_frame_arguments_all, print_frame_arguments_scalars)
(print_frame_arguments_none): Declare.
(print_raw_frame_arguments, print_entry_values): Delete.
(user_frame_print_options): New.
(boolean_option_def, enum_option_def, frame_print_option_defs):
New.
(struct backtrace_cmd_options): New.
(bt_flag_option_def): New.
(backtrace_command_option_defs): New.
(print_stack_frame): Pass down USER_FRAME_PRINT_OPTIONS.
(print_frame_arg, read_frame_arg, print_frame_args)
(print_frame_info, print_frame): Add frame_print_options parameter
and use it.
(info_frame_command_core): Pass down USER_FRAME_PRINT_OPTIONS.
(backtrace_command_1): Add frame_print_options and
backtrace_cmd_options parameters and use them.
(make_backtrace_options_def_group): New.
(backtrace_command): Process command options with
gdb::option::process_options.
(backtrace_command_completer): New.
(_initialize_stack): Extend "backtrace"'s help to mention
supported options. Install completer for "backtrace".
Install some settings commands with add_setshow_cmds_for_options.
gdb/testsuite/ChangeLog:
2019-06-13 Pedro Alves <palves@redhat.com>
* gdb.base/options.exp (test-backtrace): New.
(top level): Call it.
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This commit applies all changes made after running the gdb/copyright.py
script.
Note that one file was flagged by the script, due to an invalid
copyright header
(gdb/unittests/basic_string_view/element_access/char/empty.cc).
As the file was copied from GCC's libstdc++-v3 testsuite, this commit
leaves this file untouched for the time being; a patch to fix the header
was sent to gcc-patches first.
gdb/ChangeLog:
Update copyright year range in all GDB files.
|
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I am currently working with these functions, and though this renaming
could help to reason about the code. Some functions take a frame and
will return the value associated to that frame, others will return the
value associated to the previous frame. Those usually conveniently
contain "unwind" in their name, but naming the variable next_frame
instead of frame helps remembering which frame we are dealing with.
I also included a little typo fix at the top of frame.h.
gdb/ChangeLog:
* frame.c (frame_register_unwind): Change parameter name.
(frame_unwind_register): Likewise.
(frame_unwind_register_value): Likewise.
(frame_unwind_register_signed): Likewise.
(frame_unwind_register_unsigned): Likewise.
* frame.h (frame_register_unwind): Likewise.
(frame_unwind_register): Likewise.
(frame_unwind_register_value): Likewise.
(frame_unwind_register_signed): Likewise.
(frame_unwind_register_unsigned): Likewise.
(frame_unwind_arch): Likewise.
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PR gdb/23203 reports 'bt full' causing the currently selected frame to
change, this issue is fixed in this commit.
Add a new class scoped_restore_selected_frame that saves and restores
the selected frame. Make use of this in print_frame_local_vars to
restore the selected frame on exit.
gdb/ChangeLog:
PR gdb/23203
* frame.c
(scoped_restore_selected_frame::scoped_restore_selected_frame):
Define.
(scoped_restore_selected_frame::~scoped_restore_selected_frame):
Define.
* frame.h (class scoped_restore_selected_frame): New class.
* stack.c (print_frame_local_vars): Remove catching and rethrowing
of any exception, use scoped_restore_selected_frame to restore the
frame instead.
gdb/testsuite/ChangeLog:
PR gdb/23203
* gdb.base/bt-selected-frame.c: New file.
* gdb.base/bt-selected-frame.exp: New file.
* lib/gdb.exp (get_current_frame_number): New function.
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This patch adds a new class (type) for readonly regcache, which is
created via regcache::save. readonly_detached_regcache inherits
readable_regcache.
gdb:
2018-02-21 Yao Qi <yao.qi@linaro.org>
* dummy-frame.c (dummy_frame_cache) <prev_regcache>: Use
readonly_detached_regcache.
(dummy_frame_prev_register): Use regcache->cooked_read.
* frame.c (frame_save_as_regcache): Change return type.
(frame_pop): Update.
* frame.h (frame_save_as_regcache): Update declaration.
* inferior.h (get_infcall_suspend_state_regcache): Update
declaration.
* infrun.c (infcall_suspend_state) <registers>: use
readonly_detached_regcache.
(save_infcall_suspend_state): Don't use regcache_dup.
(get_infcall_suspend_state_regcache): Change return type.
* linux-fork.c (struct fork_info) <savedregs>: Change to
readonly_detached_regcache.
<pc>: New field.
(fork_save_infrun_state): Don't use regcache_dup.
(info_checkpoints_command): Adjust.
* mi/mi-main.c (register_changed_p): Update declaration.
(mi_cmd_data_list_changed_registers): Use
readonly_detached_regcache.
(register_changed_p): Change parameter type to
readonly_detached_regcache.
* ppc-linux-tdep.c (ppu2spu_cache) <regcache>: Use
readonly_detached_regcache.
(ppu2spu_sniffer): Construct a new readonly_detached_regcache.
* regcache.c (readonly_detached_regcache::readonly_detached_regcache):
New.
(regcache::save): Move it to reg_buffer.
(regcache::restore): Change parameter type.
(regcache_dup): Remove.
* regcache.h (reg_buffer) <save>: New method.
(readonly_detached_regcache): New class.
* spu-tdep.c (spu2ppu_cache) <regcache>: Use
readonly_detached_regcache.
(spu2ppu_sniffer): Construct a new readonly_detached_regcache.
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gdb/ChangeLog:
Update copyright year range in all GDB files
|
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This patch constifies add_info and updates all the info commands. The
bulk of this patch was written using a script; and then I did a manual
pass to fix up the remaining compilation errors.
I could not compile every changed file; in particular nto-procfs.c,
gnu-nat.c, and darwin-nat-info.c; but I at least tried to check the
correctness by inspection.
gdb/ChangeLog
2017-11-07 Tom Tromey <tom@tromey.com>
* frame.h (info_locals_command, info_args_command): Constify.
* auto-load.h (auto_load_info_scripts): Constify.
* inferior.h (registers_info): Constify.
* copying.c: Rebuild.
* copying.awk: Constify generated commands.
* auto-load.c (auto_load_info_scripts)
(info_auto_load_gdb_scripts): Constify.
* cli/cli-decode.c (struct cmd_list_element): Take a
cmd_const_cfunc_ftype.
* command.h (add_info): Take a cmd_const_cfunc_ftype.
* tui/tui-win.c (tui_all_windows_info): Constify.
* python/py-auto-load.c (info_auto_load_python_scripts):
Constify.
* cli/cli-cmds.c (show_command): Remove non-const overload.
* tracepoint.c (info_tvariables_command, info_scope_command):
Constify.
(info_static_tracepoint_markers_command): Constify.
* thread.c (info_threads_command): Constify.
(print_thread_info_1): Constify.
* target.c (info_target_command): Constify.
* symtab.c (info_sources_command, info_functions_command)
(info_types_command): Constify.
(info_variables_command): Remove non-const overload.
* symfile.c (info_ext_lang_command): Constify.
* stack.c (info_frame_command, info_locals_command)
(info_args_command): Constify.
(backtrace_command): Remove non-const overload.
* source.c (info_source_command, info_line_command): Constify.
* solib.c (info_sharedlibrary_command): Constify.
* skip.c (info_skip_command): Constify.
* ser-go32.c (info_serial_command): Constify.
* reverse.c (info_bookmarks_command): Constify.
* printcmd.c (info_symbol_command, info_address_command)
(info_display_command): Constify.
* osdata.c (info_osdata_command): Constify.
* objc-lang.c (info_selectors_command, info_classes_command):
Constify.
* nto-procfs.c (procfs_pidlist, procfs_meminfo): Constify.
* memattr.c (info_mem_command): Constify.
* macrocmd.c (info_macro_command, info_macros_command): Constify.
* linux-fork.c (info_checkpoints_command): Constify.
* infrun.c (info_signals_command): Constify.
* inflow.c (info_terminal_command): Constify.
* inferior.c (info_inferiors_command): Constify.
(print_inferior): Constify.
* infcmd.c (info_program_command, info_all_registers_command)
(info_registers_command, info_vector_command)
(info_float_command): Constify.
(registers_info): Constify.
* gnu-nat.c (info_send_rights_cmd, info_recv_rights_cmd)
(info_port_sets_cmd, info_dead_names_cmd, info_port_rights_cmd):
Constify.
* f-valprint.c (info_common_command): Constify.
* dcache.c (info_dcache_command): Constify.
(dcache_info_1): Constify.
* darwin-nat-info.c (info_mach_tasks_command)
(info_mach_task_command, info_mach_ports_command)
(info_mach_port_command, info_mach_threads_command)
(info_mach_thread_command, info_mach_regions_command)
(info_mach_regions_recurse_command, info_mach_region_command)
(info_mach_exceptions_command): Constify.
(get_task_from_args): Constify.
* cp-support.c (info_vtbl_command): Constify.
* breakpoint.c (info_watchpoints_command)
(info_tracepoints_command): Constify.
(info_breakpoints_command): Remove non-const overload.
* avr-tdep.c (avr_io_reg_read_command): Constify.
* auxv.c (info_auxv_command): Constify.
* ada-tasks.c (info_tasks_command): Constify.
(info_task): Constify.
* ada-lang.c (info_exceptions_command): Constify.
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This changes add_com to take a cmd_const_cfunc_ftype, and then fixes
up all the command implementations.
In most cases this is trivial.
In a couple of places I had to again introduce a temporary non-const
overload. These overloads will be removed when add_info is
constified.
gdb/ChangeLog
2017-11-07 Tom Tromey <tom@tromey.com>
* solib.h (no_shared_libraries): Constify.
* frame.h (return_command): Constify.
* cli/cli-cmds.h (quit_command): Constify.
* top.h (quit_command, execute_command): Constify.
* target.h (flash_erase_command): Constify.
* inferior.h (set_inferior_args, attach_command): Constify.
* tracepoint.h (start_tracing, stop_tracing): Constify.
* breakpoint.h (break_command, tbreak_command)
(hbreak_command_wrapper, thbreak_command_wrapper)
(rbreak_command_wrapper, watch_command_wrapper)
(awatch_command_wrapper, rwatch_command_wrapper)
(get_tracepoint_by_number): Constify.
* symtab.c (info_variables_command, rbreak_command)
(symtab_symbol_info): Constify.
(info_variables_command): Add non-const overload.
* top.c (dont_repeat_command): Constify.
* breakpoint.c (ignore_command, commands_command)
(condition_command, tbreak_command, hbreak_command)
(thbreak_command, clear_command, break_command)
(info_breakpoints_command, watch_command, rwatch_command)
(awatch_command, trace_command, ftrace_command, strace_command)
(trace_pass_command, break_range_command, dprintf_command)
(agent_printf_command, get_tracepoint_by_number)
(watch_maybe_just_location, trace_pass_command): Constify.
(info_breakpoints_command): Add non-const overload.
* tracefile.c (tsave_command): Constify.
* infcmd.c (attach_command, disconnect_command, signal_command)
(queue_signal_command, stepi_command, nexti_command)
(finish_command, next_command, step_command, until_command)
(advance_command, jump_command, continue_command, run_command)
(start_command, starti_command, interrupt_command)
(run_command_1, set_inferior_args, step_1): Constify.
* inferior.c (add_inferior_command, remove_inferior_command)
(clone_inferior_command): Constify.
* linux-fork.c (checkpoint_command, restart_command): Constify.
* windows-nat.c (signal_event_command): Constify.
* guile/guile.c (guile_repl_command, guile_command): Constify.
* printcmd.c (x_command, display_command, printf_command)
(output_command, set_command, call_command, print_command)
(eval_command): Constify.
(non_const_set_command): Remove.
(_initialize_printcmd): Update.
* source.c (forward_search_command, reverse_search_command):
Constify.
* jit.c (jit_reader_load_command, jit_reader_unload_command):
Constify.
* infrun.c (handle_command): Constify.
* memattr.c (mem_command): Constify.
* stack.c (return_command, up_command, up_silently_command)
(down_command, down_silently_command, frame_command)
(backtrace_command, func_command, backtrace_command_1): Constify.
(backtrace_command): Add non-const overload.
* remote-sim.c (simulator_command): Constify.
* exec.c (set_section_command): Constify.
* tracepoint.c (tdump_command, trace_variable_command)
(tstatus_command, tstop_command, tstart_command)
(end_actions_pseudocommand, while_stepping_pseudocommand)
(collect_pseudocommand, teval_pseudocommand, actions_command)
(start_tracing, stop_tracing): Constify.
* value.c (init_if_undefined_command): Constify.
* tui/tui-stack.c (tui_update_command): Constify.
* tui/tui-win.c (tui_refresh_all_command)
(tui_set_tab_width_command, tui_set_win_height_command)
(tui_set_focus_command, tui_scroll_forward_command)
(tui_scroll_backward_command, tui_scroll_left_command)
(tui_scroll_right_command, parse_scrolling_args, tui_set_focus)
(tui_set_win_height): Constify.
* tui/tui-layout.c (tui_layout_command): Constify.
* procfs.c (proc_trace_syscalls, proc_trace_sysentry_cmd)
(proc_trace_sysexit_cmd, proc_untrace_sysentry_cmd)
(proc_untrace_sysexit_cmd): Constify.
* remote.c (threadlist_test_cmd, threadinfo_test_cmd)
(threadset_test_cmd, threadlist_update_test_cmd)
(threadalive_test): Constify.
* objc-lang.c (print_object_command): Constify.
* command.h (add_com): Constify.
* cli/cli-dump.c (restore_command): Constify.
* cli/cli-cmds.c (pwd_command, echo_command, quit_command)
(help_command, complete_command, shell_command, edit_command)
(list_command, disassemble_command, make_command)
(apropos_command, alias_command): Constify.
* cli/cli-script.c (document_command, define_command)
(while_command, if_command, validate_comname): Constify.
* cli/cli-decode.c (struct cmd_list_element): Change type of
"fun".
* target.c (do_monitor_command, flash_erase_command): Constify.
* regcache.c (reg_flush_command): Constify.
* reverse.c (reverse_step, reverse_next, reverse_stepi)
(reverse_nexti, reverse_continue, reverse_finish)
(save_bookmark_command, goto_bookmark_command)
(exec_reverse_once): Constify.
* python/python.c (python_interactive_command, python_command):
Constify.
* typeprint.c (ptype_command, whatis_command, whatis_exp):
Constify.
* solib.c (sharedlibrary_command, no_shared_libraries): Constify.
* gcore.c (gcore_command): Constify.
|
|
regcache::m_aspace is a const, never changed during the lifetime of
regcache object. The address_space object is a const object too.
gdb:
2017-11-02 Yao Qi <yao.qi@linaro.org>
* breakpoint.c (insert_single_step_breakpoints): Update.
* frame.c (struct frame_info) <aspace>: Add const.
(frame_save_as_regcache): Add const.
(get_frame_address_space): Return const address_space *.
* frame.h (get_frame_address_space): Update declaration.
* infrun.c (struct step_over_info) <aspace>: Add const.
(set_step_over_info): Make aspace const.
(displaced_step_prepare_throw): Change variable const.
(resume): Likewise.
(proceed): Likewise.
(adjust_pc_after_break): Likewise.
(save_waitstatus): Likewise.
(handle_signal_stop): Likewise.
(keep_going_pass_signal): Likewise.
* jit.c (jit_frame_sniffer): Add const.
* mips-tdep.c (mips_single_step_through_delay): Likewise.
* ppc-linux-tdep.c (ppu2spu_sniffer): Likewise.
* record-full.c (record_full_wait_1): Likewise.
* regcache.c (regcache::regcache): Change parameter to const.
* regcache.h (regcache::regcache): Likewise.
(regcache::aspace): Return const address_space *.
(regcache) <m_aspace>: Add const.
|
|
Currently frame_prepare_for_sniffer returns a cleanup. This patch
changes it to return void, and exposes frame_cleanup_after_sniffer to
the caller.
Normally I would write an RAII class for this sort of thing; but
because there was just a single caller of frame_prepare_for_sniffer,
and because this caller is already using try/catch, I thought it
seemed ok to require explicit calls in this instance.
Regression tested by the buildbot.
gdb/ChangeLog
2017-10-08 Tom Tromey <tom@tromey.com>
* frame-unwind.c (frame_unwind_try_unwinder): Update.
* frame.h (frame_cleanup_after_sniffer): Declare.
(frame_prepare_for_sniffer): Return void.
* frame.c (frame_cleanup_after_sniffer): No longer static. Change
type of argument.
(frame_prepare_for_sniffer): Return void.
|
|
A following patch will remove this hack from within regcache's
implementation:
struct regcache *
get_thread_arch_regcache (ptid_t ptid, struct gdbarch *gdbarch)
{
struct address_space *aspace;
/* For the benefit of "maint print registers" & co when debugging an
executable, allow dumping the regcache even when there is no
thread selected (target_thread_address_space internal-errors if
no address space is found). Note that normal user commands will
fail higher up on the call stack due to no
target_has_registers. */
aspace = (ptid_equal (null_ptid, ptid)
? NULL
: target_thread_address_space (ptid));
i.e., it'll no longer be possible to try to build a regcache for
null_ptid. That change alone would regress the gdbarch self tests
though, causing this:
(gdb) maintenance selftest
[...]
Running selftest register_to_value.
src/gdb/inferior.c:309: internal-error: inferior* find_inferior_pid(int): Assertion `pid != 0' failed.
A problem internal to GDB has been detected,
further debugging may prove unreliable.
Quit this debugging session? (y or n) FAIL: gdb.gdb/unittest.exp: maintenance selftest (GDB internal error)
The problem is that the way the mocking environment for those unit
tests is written is a bit fragile: it creates a special purpose
regcache (and sentinel's frame), using whatever is the current
inferior_ptid (usually null_ptid), and assumes get_current_regcache
will find that in the regcache::current_regcache list.
This commit changes the way the mock environment is created. It
eliminates the special regcache and frame and instead creates a fuller
mock environment, with a custom mock target_ops, and then a mock
inferior and thread "running" on that target.
If there's already a running target when you type "maint selftest",
then we error out, instead of pushing a new target on top of the
existing one (and thus killing the debug session). This results in:
(gdb) maint selftest
(...)
Self test failed: arch i386: target already pushed
Self test failed: arch i386:x86-64: target already pushed
Self test failed: arch i386:x64-32: target already pushed
Self test failed: arch i8086: target already pushed
Self test failed: arch i386:intel: target already pushed
Self test failed: arch i386:x86-64:intel: target already pushed
Self test failed: arch i386:x64-32:intel: target already pushed
Self test failed: arch i386:nacl: target already pushed
Self test failed: arch i386:x86-64:nacl: target already pushed
Self test failed: arch i386:x64-32:nacl: target already pushed
Self test failed: self-test failed at /home/pedro/gdb/mygit/src/gdb/selftest-arch.c:86
(...)
Ran 19 unit tests, 1 failed
I think that's OK, because self tests are really meant to be run from
a clean state right after GDB is started. I'm adding that erroring
out just as safe measure just in case someone types "maint selftest"
on the command line while already debugging something (as I've done
it).
(In my multi-target branch, where this patch originated from, we don't
actually need to error out, because there each inferior has its own
target stack).
Also, note that the current code was doing:
current_inferior()->gdbarch = gdbarch;
without taking care to restore the previous gdbarch. This means that
GDB's state was being left inconsistent after running the self tests,
further supporting the point that there's probably not much
expectation that mixing "maint selftests" and regular debugging in the
same GDB invocation really works. This patch fixes that, regardless.
gdb/ChangeLog:
2017-10-04 Pedro Alves <palves@redhat.com>
* frame.c (create_test_frame): Delete.
* frame.h (create_test_frame): Delete.
* gdbarch-selftests.c: Include gdbthread.h and target.h.
(class regcache_test): Delete.
(test_target_has_registers, test_target_has_stack)
(test_target_has_memory, test_target_prepare_to_store)
(test_target_store_registers): New functions.
(test_target_ops): New class.
(register_to_value_test): Error out if there's already a
process_stratum (or higher) target pushed. Create a fuller mock
environment, with mock target_ops, inferior, address space, thread
and inferior_ptid.
* progspace.c (struct address_space): Move to ...
* progspace.h (struct address_space): ... here.
* regcache.h (regcache::~regcache, regcache::raw_write)
[GDB_SELF_TEST]: No longer virtual.
|
|
This removes make_cleanup_regcache_xfree in favor of using
std::unique_ptr as the return type of frame_save_as_regcache.
gdb/ChangeLog
2017-09-25 Tom Tromey <tom@tromey.com>
* spu-tdep.c (spu2ppu_sniffer): Update.
* regcache.h (make_cleanup_regcache_xfree): Don't declare.
* regcache.c (do_regcache_xfree, make_cleanup_regcache_xfree):
Remove.
* ppc-linux-tdep.c (ppu2spu_sniffer): Update.
* mi/mi-main.c (mi_cmd_data_list_changed_registers): Update.
* frame.h (frame_save_as_regcache): Return std::unique_ptr.
* frame.c (frame_save_as_regcache): Return std::unique_ptr.
(frame_pop): Update.
|
|
Instead, make symtab_and_line initialize its members itself. Many
symtab_and_line declarations are moved to where the object is
initialized at the same time both for clarity and to avoid double
initialization. A few functions, like e.g., find_frame_sal are
adjusted to return the sal using normal function return instead of an
output parameter likewise to avoid having to default-construct a sal
and then immediately have the object overwritten.
gdb/ChangeLog:
2017-09-04 Pedro Alves <palves@redhat.com>
* ada-lang.c (is_known_support_routine): Move sal declaration to
where it is initialized.
* breakpoint.c (create_internal_breakpoint, init_catchpoint)
(parse_breakpoint_sals, decode_static_tracepoint_spec)
(clear_command, update_static_tracepoint): Remove init_sal
references. Move declarations closer to initializations.
* cli/cli-cmds.c (list_command): Move sal declarations closer to
initializations.
* elfread.c (elf_gnu_ifunc_resolver_stop): Remove init_sal
references. Move sal declarations closer to initializations.
* frame.c (find_frame_sal): Return a symtab_and_line via function
return instead of output parameter. Remove init_sal references.
* frame.h (find_frame_sal): Return a symtab_and_line via function
return instead of output parameter.
* guile/scm-frame.c (gdbscm_frame_sal): Adjust.
* guile/scm-symtab.c (stscm_make_sal_smob): Use in-place new
instead of memset.
(gdbscm_find_pc_line): Remove init_sal reference.
* infcall.c (call_function_by_hand_dummy): Remove init_sal
references. Move declarations closer to initializations.
* infcmd.c (set_step_frame): Update. Move declarations closer to
initializations.
(finish_backward): Remove init_sal references. Move declarations
closer to initializations.
* infrun.c (process_event_stop_test, handle_step_into_function)
(insert_hp_step_resume_breakpoint_at_frame)
(insert_step_resume_breakpoint_at_caller): Likewise.
* linespec.c (create_sals_line_offset, decode_digits_ordinary)
(symbol_to_sal): Likewise.
* probe.c (parse_probes_in_pspace): Remove init_sal reference.
* python/py-frame.c (frapy_find_sal): Move sal declaration closer
to its initialization.
* reverse.c (save_bookmark_command): Use new/delete. Remove
init_sal references. Move declarations closer to initializations.
* source.c (get_current_source_symtab_and_line): Remove brace
initialization.
(set_current_source_symtab_and_line): Now takes the sal by const
reference. Remove brace initialization.
(line_info): Remove init_sal reference.
* source.h (set_current_source_symtab_and_line): Now takes a
symtab_and_line via const reference.
* stack.c (set_current_sal_from_frame): Adjust.
(print_frame_info): Adjust.
(get_last_displayed_sal): Return the sal via function return
instead of via output parameter. Simplify.
(frame_info): Adjust.
* stack.h (get_last_displayed_sal): Return the sal via function
return instead of via output parameter.
* symtab.c (init_sal): Delete.
(find_pc_sect_line): Remove init_sal references. Move
declarations closer to initializations.
(find_function_start_sal): Remove init_sal references. Move
declarations closer to initializations.
* symtab.h (struct symtab_and_line): In-class initialize all
fields.
* tracepoint.c (set_traceframe_context)
(print_one_static_tracepoint_marker): Remove init_sal references.
Move declarations closer to initializations.
* tui/tui-disasm.c (tui_show_disassem_and_update_source): Adjust.
* tui/tui-stack.c (tui_show_frame_info): Adjust. Move
declarations closer to initializations.
* tui/tui-winsource.c (tui_update_source_window_as_is): Remove
init_sal references. Adjust.
|
|
This patch renames a few functions implementing CLI commands to follow
the style <command-name>_command, so that they are easier to search for.
gdb/ChangeLog:
* breakpoint.c (breakpoints_info): Rename to ...
(info_breakpoints_command): ... this.
(watchpoints_info): Rename to ...
(info_watchpoints_command): ... this.
(tracepoints_info): Rename to ...
(info_tracepoints_command): ... this.
(_initialize_breakpoint): Adjust.
* dcache.c (dcache_info): Rename to ...
(info_display_command): ... this.
(_initialize_dcache): Adjust.
* frame.h (args_info): Rename to ...
(info_args_command): ... this.
(locals_info): Rename to ...
(info_locals_command): ... this.
* infcmd.c (nofp_registers_info): Rename to ...
(info_registers_command): ... this.
(float_info): Rename to ...
(info_float_command): ... this.
(program_info): Rename to ...
(info_program_command): ... this.
(all_registers_info): Rename to ...
(info_all_registers_command): ... this.
(vector_info): Rename to ...
(info_vector_command): ... this.
(float_info): Rename to ...
(info_float_command): ... this.
(_initialize_infcmd): Adjust.
* inferior.h (term_info): Rename to ...
(info_terminal_command): ... this.
* inflow.c (term_info): Rename to ...
(info_terminal_command): ... this.
(_initialize_inflow): Adjust.
* infrun.c (signals_info): Rename to ...
(info_signals_command): ... this.
(_initialize_infrun): Adjust.
* objc-lang.c (classes_info): Rename to ...
(info_classes_command): ... this.
(selectors_info): Rename to ...
(info_selectors_command): ... this.
(_initialize_objc_language): Adjust.
* printcmd.c (sym_info): Rename to ...
(info_symbol_command): ... this.
(address_info): Rename to ...
(info_address_command): ... this.
(display_info): Rename to ...
(info_display_command): ... this.
(_initialize_printcmd): Adjust.
* reverse.c (bookmarks_info): Rename to ...
(info_breakpoints_command): ... this.
(_initialize_reverse): Adjust.
* ser-go32.c (dos_info): Rename to ...
(info_serial_command): ... this.
(_initialize_ser_dos): Adjust.
* skip.c (skip_info): Rename to ...
(info_skip_command): ... this.
(_initialize_step_skip): Adjust.
* source.c (line_info): Rename to ...
(info_line_command): ... this.
(source_info): Rename to ...
(info_source_command)
* stack.c (frame_info): Rename to ...
(info_frame_command): ... this.
(locals_info): Rename to ...
(info_locals_command): ... this.
(args_info): Rename to ...
(info_args_command): ... this.
(_initialize_stack): Adjust.
* symtab.c (sources_info): Rename to ...
(info_sources_command): ... this.
(variables_info): Rename to ...
(info_variables_command): ... this.
(functions_info): Rename to ...
(info_functions_command): ... this.
(types_info): Rename to ...
(info_types_command): ... this.
(_initialize_symtab): Adjust.
* target.c (target_info): Rename to ...
(info_target_command): ... this.
(initialize_targets): Adjust.
* tracepoint.c (tvariables_info): Rename to ...
(info_tvariables_command): ... this.
(scope_info): Rename to ...
(info_scope_command): ... this.
(trace_dump_actions): Adjust.
(_initialize_tracepoint): Adjust.
|
|
This patch adds one unit test for gdbarch methods register_to_value and
value_to_register. The test pass different combinations of {regnu, type}
to gdbarch_register_to_value and gdbarch_value_to_register. In order
to do the test, add a new function create_new_frame to create a fake
frame. It can be improved after we converted frame_info to class.
In order to isolate regcache (from target_ops operations on writing
registers, like target_store_registers), the sub-class of regcache in the
test override raw_write. Also, in order to get the right regcache from
get_thread_arch_aspace_regcache, the sub-class of regcache inserts itself
to current_regcache.
Suppose I incorrectly modified the size of buffer as below,
@@ -1228,7 +1228,7 @@ ia64_register_to_value (struct frame_info *frame, int regnum,
int *optimizedp, int *unavailablep)
{
struct gdbarch *gdbarch = get_frame_arch (frame);
- gdb_byte in[MAX_REGISTER_SIZE];
+ gdb_byte in[1];
/* Convert to TYPE. */
if (!get_frame_register_bytes (frame, regnum, 0,
build GDB with "-fsanitize=address" and run unittest.exp, asan can detect
such error
==2302==ERROR: AddressSanitizer: stack-buffer-overflow on address 0x7fff98193870 at pc 0xbd55ea bp 0x7fff981935a0 sp 0x7fff98193598
WRITE of size 16 at 0x7fff98193870 thread T0
#0 0xbd55e9 in frame_register_unwind(frame_info*, int, int*, int*, lval_type*, unsigned long*, int*, unsigned char*) /home/yao/SourceCode/gnu/gdb/git/gdb/frame.c:1119
#1 0xbd58c8 in frame_register(frame_info*, int, int*, int*, lval_type*, unsigned long*, int*, unsigned char*) /home/yao/SourceCode/gnu/gdb/git/gdb/frame.c:1147
#2 0xbd6e25 in get_frame_register_bytes(frame_info*, int, unsigned long, int, unsigned char*, int*, int*) /home/yao/SourceCode/gnu/gdb/git/gdb/frame.c:1427
#3 0x70080a in ia64_register_to_value /home/yao/SourceCode/gnu/gdb/git/gdb/ia64-tdep.c:1236
#4 0xbf570e in gdbarch_register_to_value(gdbarch*, frame_info*, int, type*, unsigned char*, int*, int*) /home/yao/SourceCode/gnu/gdb/git/gdb/gdbarch.c:2619
#5 0xc05975 in register_to_value_test /home/yao/SourceCode/gnu/gdb/git/gdb/gdbarch-selftests.c:131
Or, even if GDB is not built with asan, GDB just crashes.
*** stack smashing detected ***: ./gdb terminated
Aborted (core dumped)
gdb:
2017-05-24 Yao Qi <yao.qi@linaro.org>
* Makefile.in (SFILES): Add gdbarch-selftests.c.
(COMMON_OBS): Add gdbarch-selftests.o.
* frame.c [GDB_SELF_TESTS] (create_new_frame): New function.
* frame.h [GDB_SELF_TESTS] (create_new_frame): Declare.
* gdbarch-selftests.c: New file.
* regcache.h (regcache) <~regcache>: Mark it virtual if
GDB_SELF_TEST.
<raw_write>: Likewise.
|
|
This applies the second part of GDB's End of Year Procedure, which
updates the copyright year range in all of GDB's files.
gdb/ChangeLog:
Update copyright year range in all GDB files.
|
|
The VALUE_FRAME_ID macro provides access to a member in struct value
that's used to hold the frame id that's used when determining a
register's value or when assigning to a register. The underlying
member has a long and obscure name. I won't refer to it here, but
will simply refer to VALUE_FRAME_ID as if it's the struct value member
instead of being a convenient macro.
At the moment, without this patch in place, VALUE_FRAME_ID is set in
value_of_register_lazy() and several other locations to hold the frame
id of the frame passed to those functions.
VALUE_FRAME_ID is used in the lval_register case of
value_fetch_lazy(). To fetch the register's value, it calls
get_frame_register_value() which, in turn, calls
frame_unwind_register_value() with frame->next.
A python based unwinder may wish to determine the value of a register
or evaluate an expression containing a register. When it does this,
value_fetch_lazy() will be called under some circumstances. It will
attempt to determine the frame id associated with the frame passed to
it. In so doing, it will end up back in the frame sniffer of the very
same python unwinder that's attempting to learn the value of a
register as part of the sniffing operation. This recursion is not
desirable.
As noted above, when value_fetch_lazy() wants to fetch a register's
value, it does so (indirectly) by unwinding from frame->next.
With this in mind, a solution suggests itself: Change VALUE_FRAME_ID
to hold the frame id associated with the next frame. Then, when it
comes time to obtain the value associated with the register, we can
simply unwind from the frame corresponding to the frame id stored in
VALUE_FRAME_ID. This neatly avoids the python unwinder recursion
problem by changing when the "next" operation occurs. Instead of the
"next" operation occuring when the register value is fetched, it
occurs earlier on when assigning a frame id to VALUE_FRAME_ID.
(Thanks to Pedro for this suggestion.)
This patch implements this idea.
It builds on the patch "Distinguish sentinel frame from null frame".
Without that work in place, it's necessary to check for null_id at
several places and then obtain the sentinel frame.
It also renames most occurences of VALUE_FRAME_ID to
VALUE_NEXT_FRAME_ID to reflect the new meaning of this field.
There are several uses of VALUE_FRAME_ID which were not changed. In
each case, the original meaning of VALUE_FRAME_ID is required to get
correct results. In all but one of these uses, either
put_frame_register_bytes() or get_frame_register_bytes() is being
called with the frame value obtained from VALUE_FRAME_ID. Both of
these functions perform some unwinding by performing a "->next"
operation on the frame passed to it. If we were to use the new
VALUE_NEXT_FRAME_ID macro, this would effectively do two "->next"
operations, which is not what we want.
The VALUE_FRAME_ID macro has been redefined in terms of
VALUE_NEXT_FRAME_ID. It simply fetches the previous frame's id,
providing this id as the value of the macro.
gdb/ChangeLog:
* value.h (VALUE_FRAME_ID): Rename to VALUE_NEXT_FRAME_ID. Update
comment. Create new VALUE_FRAME_ID which is defined in terms of
VALUE_NEXT_FRAME_ID.
(deprecated_value_frame_id_hack): Rename to
deprecated_value_next_frame_id_hack.
* dwarf2loc.c, findvar.c, frame-unwind.c, sentinel-frame.c,
valarith.c, valops.c, value.c: Adjust nearly all occurences of
VALUE_FRAME_ID to VALUE_NEXT_FRAME_ID. Add comments for those
which did not change.
* value.c (struct value): Rename frame_id field to next_frame_id.
Update comment.
(deprecated_value_frame_id_hack): Rename to
deprecated_value_next_frame_id_hack.
(value_fetch_lazy): Call frame_unwind_register_value()
instead of get_frame_register_value().
* frame.c (get_prev_frame_id_by_id): New function.
* frame.h (get_prev_frame_id_by_id): Declare.
* dwarf2loc.c (dwarf2_evaluate_loc_desc_full): Make
VALUE_NEXT_FRAME_ID refer to the next frame.
* findvar.c (value_of_register_lazy): Likewise.
(default_value_from_register): Likewise.
(value_from_register): Likewise.
* frame_unwind.c (frame_unwind_got_optimized): Likewise.
* sentinel-frame.c (sentinel_frame_prev_register): Likewise.
* value.h (VALUE_FRAME_ID): Update comment describing this macro.
|
|
This patch replaces the `current_frame' static global in frame.c with
`sentinel_frame'. It also makes the sentinel frame id unique and
different from the null frame.
By itself, there is not much point to this patch, but it makes
the code cleaner for the VALUE_FRAME_ID changes in another patch.
Since we now allow "navigation" to the sentinel frame, it removes
the necessity of adding special cases to other parts of GDB.
Note that a new function, get_next_frame_sentinel_okay, is introduced
in this patch. It will be used by the VALUE_FRAME_ID changes that
I've made.
Thanks to Pedro Alves for this suggestion.
gdb/ChangeLog:
* frame.h (enum frame_id_stack_status): Add FID_STACK_SENTINEL.
(struct frame_id): Increase number of bits required for storing
stack status to 3 from 2.
(sentinel_frame_id): New declaration.
(get_next_frame_sentinel_okay): Declare.
(frame_find_by_id_sentinel_okay): Declare.
* frame.c (current_frame): Rename this static global to...
(sentinel_frame): ...this static global, which has also been
moved an earlier location in the file.
(fprint_frame_id): Add case for sentinel frame id.
(get_frame_id): Return early for sentinel frame.
(sentinel_frame_id): Define.
(frame_find_by_id): Add case for sentinel_frame_id.
(create_sentinel_frame): Use sentinel_frame_id for this_id.value
instead of null_frame_id.
(get_current_frame): Add local declaration for `current_frame'.
Remove local declaration for `sentinel_frame.'
(get_next_frame_sentinel_okay): New function.
(reinit_frame_cache): Use `sentinel_frame' in place of
`current_frame'.
|
|
Fixes this failure when building in C mode. I think it's relevant for master
as well, since it's a good practice to include (or forward-declare) what you
use.
In file included from ../../binutils-gdb/gdb/gdbarch.h:38:0,
from ../../binutils-gdb/gdb/defs.h:653,
from ../../binutils-gdb/gdb/dictionary.c:23:
../../binutils-gdb/gdb/frame.h:710:48: warning: ‘struct ui_out’ declared inside parameter list will not be visible outside of this definition or declaration
extern void print_stack_frame_to_uiout (struct ui_out *uiout,
gdb/ChangeLog:
* frame.h: Forward-declare struct ui_out.
|
|
With this patch, when an inferior, thread or frame is explicitly
selected by the user, notifications will appear on all CLI and MI UIs.
When a GDB console is integrated in a front-end, this allows the
front-end to follow a selection made by the user ont he CLI, and it
informs the user about selection changes made behind the scenes by the
front-end.
This patch addresses PR gdb/20487.
In order to communicate frame changes to the front-end, this patch adds
a new field to the =thread-selected event for the selected frame. The
idea is that since inferior/thread/frame can be seen as a composition,
it makes sense to send them together in the same event. The vision
would be to eventually send the inferior information as well, if we find
that it's needed, although the "=thread-selected" event would be
ill-named for that job.
Front-ends need to handle this new field if they want to follow the
frame selection changes that originate from the console. The format of
the frame attribute is the same as what is found in the *stopped events.
Here's a detailed example for each command and the events they generate:
thread
------
1. CLI command:
thread 1.3
MI event:
=thread-selected,id="3",frame={...}
2. MI command:
-thread-select 3
CLI event:
[Switching to thread 1.3 ...]
3. MI command (CLI-in-MI):
thread 1.3
MI event/reply:
&"thread 1.3\n"
~"#0 child_sub_function () ...
=thread-selected,id="3",frame={level="0",...}
^done
frame
-----
1. CLI command:
frame 1
MI event:
=thread-selected,id="3",frame={level="1",...}
2. MI command:
-stack-select-frame 1
CLI event:
#1 0x00000000004007f0 in child_function...
3. MI command (CLI-in-MI):
frame 1
MI event/reply:
&"frame 1\n"
~"#1 0x00000000004007f9 in ..."
=thread-selected,id="3",frame={level="1"...}
^done
inferior
--------
Inferior selection events only go from the console to MI, since there's
no way to select the inferior in pure MI.
1. CLI command:
inferior 2
MI event:
=thread-selected,id="3"
Note that if the user selects an inferior that is not started or exited,
the MI doesn't receive a notification. Since there is no threads to
select, the =thread-selected event does not apply...
2. MI command (CLI-in-MI):
inferior 2
MI event/reply:
&"inferior 2\n"
~"[Switching to inferior 2 ...]"
=thread-selected,id="4",frame={level="0"...}
^done
Internal implementation detail: this patch makes it possible to suppress
notifications caused by a CLI command, like what is done in mi-interp.c.
This means that it's now possible to use the
add_com_suppress_notification function to register a command with some
event suppressed. It is used to implement the select-frame command in
this patch.
The function command_notifies_uscc_observer was added to extract
the rather complicated logical expression from the if statement. It is
also now clearer what that logic does: if the command used by the user
already notifies the user_selected_context_changed observer, there is
not need to notify it again. It therefore protects again emitting the
event twice.
No regressions, tested on ubuntu 14.04 x86 with target boards unix and
native-extended-gdbserver.
gdb/ChangeLog:
YYYY-MM-DD Antoine Tremblay <antoine.tremblay@ericsson.com>
YYYY-MM-DD Simon Marchi <simon.marchi@ericsson.com>
PR gdb/20487
* NEWS: Mention new frame field of =thread-selected event.
* cli/cli-decode.c (add_cmd): Initialize c->suppress_notification.
(add_com_suppress_notification): New function definition.
(cmd_func): Set and restore the suppress_notification flag.
* cli/cli-deicode.h (struct cmd_list_element)
<suppress_notification>: New field.
* cli/cli-interp.c (cli_suppress_notification): New global variable.
(cli_on_user_selected_context_changed): New function.
(_initialize_cli_interp): Attach to user_selected_context_changed
observer.
* command.h (struct cli_suppress_notification): New structure.
(cli_suppress_notification): New global variable declaration.
(add_com_suppress_notification): New function declaration.
* defs.h (enum user_selected_what_flag): New enum.
(user_selected_what): New enum flag type.
* frame.h (print_stack_frame_to_uiout): New function declaration.
* gdbthread.h (print_selected_thread_frame): New function declaration.
* inferior.c (print_selected_inferior): New function definition.
(inferior_command): Remove printing of inferior/thread/frame switch
notifications, notify user_selected_context_changed observer.
* inferior.h (print_selected_inferior): New function declaration.
* mi/mi-cmds.c (struct mi_cmd): Add user_selected_context
suppression to stack-select-frame and thread-select commands.
* mi/mi-interp.c (struct mi_suppress_notification)
<user_selected_context>: Initialize.
(mi_user_selected_context_changed): New function definition.
(_initialize_mi_interp): Attach to user_selected_context_changed.
* mi/mi-main.c (mi_cmd_thread_select): Print thread selection reply.
(mi_execute_command): Handle notification suppression. Notify
user_selected_context_changed observer on thread change instead of printing
event directly. Don't send it if command already sends the notification.
(command_notifies_uscc_observer): New function.
(mi_cmd_execute): Don't handle notification suppression.
* mi/mi-main.h (struct mi_suppress_notification)
<user_selected_context>: New field.
* stack.c (print_stack_frame_to_uiout): New function definition.
(select_frame_command): Notify user_selected_context_changed
observer.
(frame_command): Call print_selected_thread_frame if there's no frame
change or notify user_selected_context_changed observer if there is.
(up_command): Notify user_selected_context_changed observer.
(down_command): Likewise.
(_initialize_stack): Suppress user_selected_context notification for
command select-frame.
* thread.c (thread_command): Notify
user_selected_context_changed if the thread has changed, print
thread info directly if it hasn't.
(do_captured_thread_select): Do not print thread switch event.
(print_selected_thread_frame): New function definition.
* tui/tui-interp.c (tui_on_user_selected_context_changed):
New function definition.
(_initialize_tui_interp): Attach to user_selected_context_changed
observer.
gdb/doc/ChangeLog:
PR gdb/20487
* gdb.texinfo (Context management): Update mention of frame
change notifications.
(gdb/mi Async Records): Document frame field in
=thread-select event.
* observer.texi (GDB Observers): New user_selected_context_changed
observer.
gdb/testsuite/ChangeLog:
PR gdb/20487
* gdb.mi/mi-pthreads.exp (check_mi_thread_command_set): Adapt
=thread-select-event check.
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Nowadays, GDB can't insert breakpoint on the return address of the
exception handler on ARM M-profile, because the address is a magic
one 0xfffffff9,
(gdb) bt
#0 CT32B1_IRQHandler () at ../src/timer.c:67
#1 <signal handler called>
#2 main () at ../src/timer.c:127
(gdb) info frame
Stack level 0, frame at 0x200ffa8:
pc = 0x4ec in CT32B1_IRQHandler (../src/timer.c:67); saved pc = 0xfffffff9
called by frame at 0x200ffc8
source language c.
Arglist at 0x200ffa0, args:
Locals at 0x200ffa0, Previous frame's sp is 0x200ffa8
Saved registers:
r7 at 0x200ffa0, lr at 0x200ffa4
(gdb) x/x 0xfffffff9
0xfffffff9: Cannot access memory at address 0xfffffff9
(gdb) finish
Run till exit from #0 CT32B1_IRQHandler () at ../src/timer.c:67
Ed:15: Target error from Set break/watch: Et:96: Pseudo-address (0xFFFFFFxx) for EXC_RETURN is invalid (GDB error?)
Warning:
Cannot insert hardware breakpoint 0.
Could not insert hardware breakpoints:
You may have requested too many hardware breakpoints/watchpoints.
Command aborted.
even some debug probe can't set hardware breakpoint on the magic
address too,
(gdb) hbreak *0xfffffff9
Hardware assisted breakpoint 2 at 0xfffffff9
(gdb) c
Continuing.
Ed:15: Target error from Set break/watch: Et:96: Pseudo-address (0xFFFFFFxx) for EXC_RETURN is invalid (GDB error?)
Warning:
Cannot insert hardware breakpoint 2.
Could not insert hardware breakpoints:
You may have requested too many hardware breakpoints/watchpoints.
Command aborted.
The problem described above is quite similar to PR 8841, in which GDB
can't set breakpoint on signal trampoline, which is mapped to a read-only
page by kernel. The rationale of this patch is to skip "unwritable"
frames when looking for caller frames in command "finish", and a new
gdbarch method code_of_frame_writable is added. This patch fixes
the problem on ARM cortex-m target, but it can be used to fix
PR 8841 too.
gdb:
2016-05-10 Yao Qi <yao.qi@arm.com>
* arch-utils.c (default_code_of_frame_writable): New function.
* arch-utils.h (default_code_of_frame_writable): Declare.
* arm-tdep.c (arm_code_of_frame_writable): New function.
(arm_gdbarch_init): Install gdbarch method
code_of_frame_writable if the target is M-profile.
* frame.c (skip_unwritable_frames): New function.
* frame.h (skip_unwritable_frames): Declare.
* gdbarch.sh (code_of_frame_writable): New.
* gdbarch.c, gdbarch.h: Re-generated.
* infcmd.c (finish_command): Call skip_unwritable_frames.
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In skip_artificial_frames we repeatedly call get_prev_frame_always until we get
a non-inline and non-tailcall frame assuming that there must be such a frame
eventually.
For record targets, however, we may have a frame chain that consists only of
artificial frames. This leads to a crash in get_frame_type when dereferencing a
NULL frame pointer.
Change skip_artificial_frames and skip_tailcall_frames to return NULL in such a
case and modify each caller to cope with a NULL return.
In frame_unwind_caller_pc and frame_unwind_caller_arch, we simply assert that
the returned value is not NULL. Their caller was supposed to check
frame_unwind_caller_id before calling those functions.
In other cases, we thrown an error.
In infcmd further move the skip_tailcall_frames call to the forward-stepping
case since we don't need a frame for reverse execution and we don't want to fail
because of that. Reverse-finish does make sense for a tailcall frame.
gdb/
* frame.h (skip_tailcall_frames): Update comment.
* frame.c (skip_artificial_frames, skip_tailcall_frames): Return NULL
if only artificial frames are found. Update comment.
(frame_unwind_caller_id): Handle NULL return.
(frame_unwind_caller_pc, frame_unwind_caller_arch): Assert that
skip_artificial_frames does not return NULL.
(frame_pop): Add an error if only tailcall frames are found.
* infcmd.c (finish_command): Move skip_tailcall_frames call into forward-
execution case. Add an error if only tailcall frames are found.
testsuite/
* gdb.btrace/tailcall-only.exp: New.
* gdb.btrace/tailcall-only.c: New.
* gdb.btrace/x86_64-tailcall-only.S: New.
* gdb.btrace/i686-tailcall-only.S: New.
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Add a new function skip_tailcall_frames to skip TAILCALL_FRAME frames.
gdb/
* frame.h (skip_tailcall_frames): New.
* frame.c (skip_tailcall_frames): New.
(frame_pop): Call skip_tailcall_frames.
* infcmd.c (finish_command): Call skip_tailcall_frames.
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gdb/ChangeLog:
Update year range in copyright notice of all files.
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The get_frame_language feels like it would be more at home in frame.c
rather than in stack.c, while the declaration, that is currently in
language.h can be moved into frame.h to match.
A couple of new includes are added, but otherwise no substantial change
here.
gdb/ChangeLog:
* stack.c (get_frame_language): Moved ...
* frame.c (get_frame_language): ... to here.
* language.h (get_frame_language): Declaration moved to frame.h.
* frame.h: Add language.h include, for language enum.
(get_frame_language): Declaration moved from language.h.
* language.c: Add frame.h include.
* top.c: Add frame.h include.
* symtab.h (struct obj_section): Declare.
(struct cmd_list_element): Declare.
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The select_frame hook is used by TUI to update TUI's frame and register
information following changes to the selected frame. The problem with
this hook is that it gets called after every single frame change, even
if the frame change is only temporary or internal. This is the primary
cause of flickering and slowdown when running the inferior under TUI
with conditional breakpoints set. Internal GDB events are the source of
many calls to select_frame and these internal events are triggered
frequently, especially when a few conditional breakpoints are set.
This patch removes the select_frame hook altogether and instead makes
the frame and register information get updated in two key places (using
observers): after an inferior stops, and right before displaying a
prompt. The latter hook covers the case when frame information must be
updated following a call to "up", "down" or "frame", and the former
covers the case when frame and register information must be updated
after a call to "continue", "step", etc. or after the inferior stops in
async execution mode. Together these hooks should cover all the cases
when frame information ought to be refreshed (and when the relevant
windows ought to be subsequently updated).
The print_frame_info_listing hook is also effectively obsolete now, but
it still must be set while the TUI is active because its caller
print_frame_info will otherwise assume that the CLI is active, and will
print the frame informaion accordingly. So this patch also sets the
print_frame_info_listing hook to a dummy callback, in lieu of outright
removing it yet.
Effectively, with this patch, frame/PC changes that do not immediately
precede an inferior-stop event or a prompt display event no longer cause
TUI's frame and register information to be updated.
And as a result of this change and of the previous change to
tui_show_frame_info, the TUI is much more disciplined about updating the
screen, and so the flicker as described in the PR is totally gone.
gdb/ChangeLog:
PR tui/13378
* frame.c (select_frame): Remove reference to
deprecated_selected_frame_level_changed_hook.
* frame.h (deprecated_selected_frame_level_changed_hook): Remove
declaration.
* stack.c (deprecated_selected_frame_level_changed_hook):
Likewise.
* tui/tui-hooks.c (tui_selected_frame_level_changed_hook):
Rename to ...
(tui_refresh_frame_and_register_information): ... this. Bail
out if there is no stack. Don't update register information
unless registers_too_p is true.
(tui_print_frame_info_listing_hook): Rename to ...
(tui_dummy_print_frame_info_listing_hook): ... this.
(tui_before_prompt): New function.
(tui_normal_stop): New function.
(tui_before_prompt_observer): New observer.
(tui_normal_stop_observer): New observer.
(tui_install_hooks): Set
deprecated_print_frame_info_listing_hook to
tui_dummy_print_frame_info_listing_hook. Register
tui_before_prompt_observer to call tui_before_prompt and
tui_normal_stop_observer to call tui_normal_stop. Remove
reference to deprecated_selected_frame_level_changed_hook.
(tui_remove_hooks): Detach and unset tui_before_prompt_observer
and tui_normal_stop_observer. Remove reference to
deprecated_selected_frame_level_changed_hook.
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gdb/ChangeLog:
Update year range in copyright notice of all files.
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This makes some spots in gdb, particularly general_symbol_info, use a
"const struct block", then fixes the fallout.
The justification is that, ordinarily, blocks ought to be readonly.
Note though that we can't add "const" in the blockvector due to block
relocation. This can be done once blocks are made independent of the
program space.
2014-06-18 Tom Tromey <tromey@redhat.com>
* varobj.c (varobj_create): Update.
* valops.c (value_of_this): Update.
* tracepoint.c (add_local_symbols, scope_info): Update.
* symtab.h (struct general_symbol_info) <block>: Now const.
* symtab.c (skip_prologue_sal)
(default_make_symbol_completion_list_break_on)
(skip_prologue_using_sal): Update.
* stack.h (iterate_over_block_locals)
(iterate_over_block_local_vars): Update.
* stack.c (print_frame_args): Update.
(iterate_over_block_locals, iterate_over_block_local_vars): Make
parameter const.
(get_selected_block): Make return type const.
* python/py-frame.c (frapy_block): Update.
* python/py-block.c (gdbpy_block_for_pc): Update.
* p-exp.y (%union) <bval>: Now const.
* mi/mi-cmd-stack.c (list_args_or_locals): Update.
* mdebugread.c (mylookup_symbol, parse_procedure): Update.
* m2-exp.y (%union) <bval>: Now const.
* linespec.c (get_current_search_block): Make return type const.
(create_sals_line_offset, find_label_symbols): Update.
* inline-frame.c (inline_frame_sniffer, skip_inline_frames):
Update.
(block_starting_point_at): Make "block" const.
* infrun.c (insert_exception_resume_breakpoint): Make "b" const.
(check_exception_resume): Update.
* guile/scm-frame.c (gdbscm_frame_block): Update.
* guile/scm-block.c (gdbscm_lookup_block): Update.
* frame.h (get_frame_block): Update.
(get_selected_block): Make return type const.
* frame.c (frame_id_inner): Update.
* f-valprint.c (info_common_command_for_block)
(info_common_command): Update.
* dwarf2loc.c (dwarf2_find_location_expression)
(dwarf_expr_frame_base, dwarf2_compile_expr_to_ax)
(locexpr_describe_location_piece): Update.
* c-exp.y (%union) <bval>: Now const.
* breakpoint.c (resolve_sal_pc): Update.
* blockframe.c (get_frame_block):Make return type const.
(get_pc_function_start, get_frame_function, find_pc_sect_function)
(block_innermost_frame): Update.
* block.h (blockvector_for_pc, blockvector_for_pc_sect)
(block_for_pc, block_for_pc_sect): Update.
* block.c (blockvector_for_pc_sect, blockvector_for_pc): Make
'pblock' const.
(block_for_pc_sect, block_for_pc): Make return type const.
* ax-gdb.c (gen_expr): Update.
* alpha-mdebug-tdep.c (find_proc_desc): Update.
* ada-lang.c (ada_read_renaming_var_value): Make 'block' const.
(ada_make_symbol_completion_list, ada_add_exceptions_from_frame)
(ada_read_var_value): Update.
* ada-exp.y (struct name_info) <block>: Now const.
(%union): Likewise.
(block_lookup): Constify.
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https://sourceware.org/ml/gdb-patches/2014-05/msg00737.html
Currently a MEMORY_ERROR raised during unwinding a frame will cause the
unwind to stop with an error message, for example:
(gdb) bt
#0 breakpt () at amd64-invalid-stack-middle.c:27
#1 0x00000000004008f0 in func5 () at amd64-invalid-stack-middle.c:32
#2 0x0000000000400900 in func4 () at amd64-invalid-stack-middle.c:38
#3 0x0000000000400910 in func3 () at amd64-invalid-stack-middle.c:44
#4 0x0000000000400928 in func2 () at amd64-invalid-stack-middle.c:50
Cannot access memory at address 0x2aaaaaab0000
However, frame #4 is marked as being the end of the stack unwind, so a
subsequent request for the backtrace looses the error message, such as:
(gdb) bt
#0 breakpt () at amd64-invalid-stack-middle.c:27
#1 0x00000000004008f0 in func5 () at amd64-invalid-stack-middle.c:32
#2 0x0000000000400900 in func4 () at amd64-invalid-stack-middle.c:38
#3 0x0000000000400910 in func3 () at amd64-invalid-stack-middle.c:44
#4 0x0000000000400928 in func2 () at amd64-invalid-stack-middle.c:50
When fetching the backtrace, or requesting the stack depth using the MI
interface the situation is even worse, the first time a request is made
we encounter the memory error and so the MI returns an error instead of
the correct result, for example:
(gdb) -stack-info-depth
^error,msg="Cannot access memory at address 0x2aaaaaab0000"
Or,
(gdb) -stack-list-frames
^error,msg="Cannot access memory at address 0x2aaaaaab0000"
However, once one of these commands has been used gdb has, internally,
walked the stack and figured that out that frame #4 is the bottom of the
stack, so the second time an MI command is tried you'll get the "expected"
result:
(gdb) -stack-info-depth
^done,depth="5"
Or,
(gdb) -stack-list-frames
^done,stack=[frame={level="0", .. snip lots .. }]
After this patch the MEMORY_ERROR encountered during the frame unwind is
attached to frame #4 as the stop reason, and is displayed in the CLI each
time the backtrace is requested. In the MI, catching the error means that
the "expected" result is returned the first time the MI command is issued.
So, from the CLI the results of the backtrace will be:
(gdb) bt
#0 breakpt () at amd64-invalid-stack-middle.c:27
#1 0x00000000004008f0 in func5 () at amd64-invalid-stack-middle.c:32
#2 0x0000000000400900 in func4 () at amd64-invalid-stack-middle.c:38
#3 0x0000000000400910 in func3 () at amd64-invalid-stack-middle.c:44
#4 0x0000000000400928 in func2 () at amd64-invalid-stack-middle.c:50
Backtrace stopped: Cannot access memory at address 0x2aaaaaab0000
Each and every time that the backtrace is requested, while the MI output
will similarly be consistently:
(gdb) -stack-info-depth
^done,depth="5"
Or,
(gdb) -stack-list-frames
^done,stack=[frame={level="0", .. snip lots .. }]
gdb/ChangeLog:
* frame.c (struct frame_info): Add stop_string field.
(get_prev_frame_always_1): Renamed from get_prev_frame_always.
(get_prev_frame_always): Old content moved into
get_prev_frame_always_1. Call get_prev_frame_always_1 inside
TRY_CATCH, handle MEMORY_ERROR exceptions.
(frame_stop_reason_string): New function definition.
* frame.h (unwind_stop_reason_to_string): Extend comment to
mention frame_stop_reason_string.
(frame_stop_reason_string): New function declaration.
* stack.c (frame_info): Switch to frame_stop_reason_string.
(backtrace_command_1): Switch to frame_stop_reason_string.
* unwind_stop_reason.def: Add UNWIND_MEMORY_ERROR.
(LAST_ENTRY): Changed to UNWIND_MEMORY_ERROR.
* guile/lib/gdb.scm: Add FRAME_UNWIND_MEMORY_ERROR to export list.
gdb/doc/ChangeLog:
* guile.texi (Frames In Guile): Mention FRAME_UNWIND_MEMORY_ERROR.
* python.texi (Frames In Python): Mention
gdb.FRAME_UNWIND_MEMORY_ERROR.
gdb/testsuite/ChangeLog:
* gdb.arch/amd64-invalid-stack-middle.exp: Update expected results.
* gdb.arch/amd64-invalid-stack-top.exp: Likewise.
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