This patch introduces a new macro, INIT_GDB_FILE. This is used to
replace the current "_initialize_" idiom when introducing a per-file
initialization function. That is, rather than write:
void _initialize_something ();
void
_initialize_something ()
{
...
}
... now you would write:
INIT_GDB_FILE (something)
{
...
}
The macro handles both the declaration and definition of the function.
The point of this approach is that it makes it harder to accidentally
cause an initializer to be omitted; see commit 2711e475 ("Ensure
cooked_index_entry self-tests are run"). Specifically, the regexp now
used by make-init-c seems harder to trick.
New in v2: un-did some erroneous changes made by the script.
The bulk of this patch was written by script.
Regression tested on x86-64 Fedora 41.
This updates the copyright headers to include 2025. I did this by
running gdb/copyright.py and then manually modifying a few files as
noted by the script.
Approved-By: Eli Zaretskii <eliz@gnu.org>
I ran codespell on gdb/*.[chyl] and fixed a bunch of simple typos.
Most of what remains is trickier, i.e., spots where a somewhat natural
name of something in the code is flagged as a typo.
Reviewed-By: Tom de Vries <tdevries@suse.de>
Frame unwinders have historically been a structure populated with
callback pointers, so that architectures (or other specific unwinders)
could install their own way to handle the inferior. However, since
moving to C++, we could use polymorphism to get the same functionality
in a more readable way. Polymorphism also makes it simpler to add new
functionality to all frame unwinders, since all that's required is
adding it to the base class.
As part of the changes to add support to disabling frame unwinders,
this commit makes the first baby step in using polymorphism for the
frame unwinders, by making frame_unwind a virtual class, and adds a
couple of new classes. The main class added is frame_unwind_legacy,
which works the same as the previous structs, using function pointers
as callbacks. This class was added to allow the transition to happen
piecemeal. New unwinders should instead follow the lead of the other
classes implemented.
2 of the others, frame_unwind_python and frame_unwind_trampoline, were added
because it seemed simpler at the moment to do that instead of reworking
the dynamic allocation to work with the legacy class, and can be used as
an example to future implementations.
Finally, the cygwin unwinder was converted to a class since it was most
of the way there already.
Reviewed-by: Thiago Jung Bauermann <thiago.bauermann@linaro.org>
Approved-By: Simon Marchi <simon.marchi@efficios.com>
Approved-By: Andrew Burgess <aburgess@redhat.com>
A future patch will add a way to disable certain unwinders based on
different characteristics. This patch aims to make it more convenient
to disable related unwinders in bulk, such as architecture specific
ones, by identifying all unwinders by which part of the code adds it.
The classes, and explanations, are as follows:
* GDB: An internal unwinder, added by GDB core, such as the unwinder
for dummy frames;
* EXTENSION: Unwinders added by extension languages;
* DEBUGINFO: Unwinders installed by the debug info reader;
* ARCH: Unwinders installed by the architecture specific code.
Reviewed-By: Eli Zaretskii <eliz@gnu.org>
Reviewed-by: Thiago Jung Bauermann <thiago.bauermann@linaro.org>
Approved-By: Simon Marchi <simon.marchi@efficios.com>
Approved-By: Andrew Burgess <aburgess@redhat.com>
This is a simple find / replace from "struct bound_minimal_symbol" to
"bound_minimal_symbol", to make things shorter and more consisten
througout. In some cases, move variable declarations where first used.
Change-Id: Ica4af11c4ac528aa842bfa49a7afe8fe77a66849
Reviewed-by: Keith Seitz <keiths@redhat.com>
Approved-By: Andrew Burgess <aburgess@redhat.com>
Most files including gdbcmd.h currently rely on it to access things
actually declared in cli/cli-cmds.h (setlist, showlist, etc). To make
things easy, replace all includes of gdbcmd.h with includes of
cli/cli-cmds.h. This might lead to some unused includes of
cli/cli-cmds.h, but it's harmless, and much faster than going through
the 170 or so files by hand.
Change-Id: I11f884d4d616c12c05f395c98bbc2892950fb00f
Approved-By: Tom Tromey <tom@tromey.com>
Move the declarations out of defs.h, and the implementations out of
findvar.c.
I opted for a new file, because this functionality of converting
integers to bytes and vice-versa seems a bit to generic to live in
findvar.c.
Change-Id: I524858fca33901ee2150c582bac16042148d2251
Approved-By: John Baldwin <jhb@FreeBSD.org>
Now that defs.h, server.h and common-defs.h are included via the
`-include` option, it is no longer necessary for source files to include
them. Remove all the inclusions of these files I could find. Update
the generation scripts where relevant.
Change-Id: Ia026cff269c1b7ae7386dd3619bc9bb6a5332837
Approved-By: Pedro Alves <pedro@palves.net>
We currently pass frames to function by value, as `frame_info_ptr`.
This is somewhat expensive:
- the size of `frame_info_ptr` is 64 bytes, which is a bit big to pass
by value
- the constructors and destructor link/unlink the object in the global
`frame_info_ptr::frame_list` list. This is an `intrusive_list`, so
it's not so bad: it's just assigning a few points, there's no memory
allocation as if it was `std::list`, but still it's useless to do
that over and over.
As suggested by Tom Tromey, change many function signatures to accept
`const frame_info_ptr &` instead of `frame_info_ptr`.
Some functions reassign their `frame_info_ptr` parameter, like:
void
the_func (frame_info_ptr frame)
{
for (; frame != nullptr; frame = get_prev_frame (frame))
{
...
}
}
I wondered what to do about them, do I leave them as-is or change them
(and need to introduce a separate local variable that can be
re-assigned). I opted for the later for consistency. It might not be
clear why some functions take `const frame_info_ptr &` while others take
`frame_info_ptr`. Also, if a function took a `frame_info_ptr` because
it did re-assign its parameter, I doubt that we would think to change it
to `const frame_info_ptr &` should the implementation change such that
it doesn't need to take `frame_info_ptr` anymore. It seems better to
have a simple rule and apply it everywhere.
Change-Id: I59d10addef687d157f82ccf4d54f5dde9a963fd0
Approved-By: Andrew Burgess <aburgess@redhat.com>
This commit is the result of the following actions:
- Running gdb/copyright.py to update all of the copyright headers to
include 2024,
- Manually updating a few files the copyright.py script told me to
update, these files had copyright headers embedded within the
file,
- Regenerating gdbsupport/Makefile.in to refresh it's copyright
date,
- Using grep to find other files that still mentioned 2023. If
these files were updated last year from 2022 to 2023 then I've
updated them this year to 2024.
I'm sure I've probably missed some dates. Feel free to fix them up as
you spot them.
The next patch introduces a new variant of gdbarch_pseudo_register_write
that takes a frame instead of a regcache for implementations to write
raw registers. Rename to old one to make it clear it's deprecated.
Change-Id: If8872c89c6f8a1edfcab983eb064248fd5ff3115
Reviewed-By: John Baldwin <jhb@FreeBSD.org>
This turns the remaining value_contents functions -- value_contents,
value_contents_all, value_contents_for_printing, and
value_contents_for_printing_const -- into methods of value. It also
converts the static functions require_not_optimized_out and
require_available to be private methods.
Approved-By: Simon Marchi <simon.marchi@efficios.com>
It's currently not clear how the ownership of gdbarch_tdep objects
works. In fact, nothing ever takes ownership of it. This is mostly
fine because we never free gdbarch objects, and thus we never free
gdbarch_tdep objects. There is an exception to that however: when
initialization fails, we do free the gdbarch object that is not going to
be used, and we free the tdep too. Currently, i386 and s390 do it.
To make things clearer, change gdbarch_alloc so that it takes ownership
of the tdep. The tdep is thus automatically freed if the gdbarch is
freed.
Change all gdbarch initialization functions to pass a new gdbarch_tdep
object to gdbarch_alloc and then retrieve a non-owning reference from
the gdbarch object.
Before this patch, the xtensa architecture had a single global instance
of xtensa_gdbarch_tdep. Since we need to pass a dynamically allocated
gdbarch_tdep_base instance to gdbarch_alloc, remove this global
instance, and dynamically allocate one as needed, like we do for all
other architectures. Make the `rmap` array externally visible and
rename it to the less collision-prone `xtensa_rmap` name.
Change-Id: Id3d70493ef80ce4bdff701c57636f4c79ed8aea2
Approved-By: Andrew Burgess <aburgess@redhat.com>
This commit is the result of running the gdb/copyright.py script,
which automated the update of the copyright year range for all
source files managed by the GDB project to be updated to include
year 2023.
Some gdb stubs may not describe the type for vector registers in the
tdesc-xml and only send bitsize="128", gdb can't deal with a reg
with default type int with bitsize==128. So Just return csky_vector_type()
for vector resgisters.
This changes GDB to use frame_info_ptr instead of frame_info *
The substitution was done with multiple sequential `sed` commands:
sed 's/^struct frame_info;/class frame_info_ptr;/'
sed 's/struct frame_info \*/frame_info_ptr /g' - which left some
issues in a few files, that were manually fixed.
sed 's/\<frame_info \*/frame_info_ptr /g'
sed 's/frame_info_ptr $/frame_info_ptr/g' - used to remove whitespace
problems.
The changed files were then manually checked and some 'sed' changes
undone, some constructors and some gets were added, according to what
made sense, and what Tromey originally did
Co-Authored-By: Bruno Larsen <blarsen@redhat.com>
Approved-by: Tom Tomey <tom@tromey.com>
After the previous few commit, gdbarch_register_name no longer returns
nullptr. This commit audits all the calls to gdbarch_register_name
and removes any code that checks the result against nullptr.
There should be no visible change after this commit.
Building on the previous commits, in this commit I remove two
instances of 'return NULL' from csky_pseudo_register_name, and replace
them with a return of the empty string.
These two are particularly interesting, and worth pulling into their
own commit, because these returns of NULL appear to be depended on
within other parts of the csky code.
In csky-linux-tdep.c in the register collect/supply code, GDB checks
for the register name being nullptr in order to decide if a target
supports a particular feature or not. I've updated the code to check
for the empty string.
I have no way of testing this change.
The reason for implementing this interface is that we want to print
GPR, PC, EPC, PSR and EPSR when the "info register" command
is executed.
A prev patch has added PC, EPC, PSR and EPSR to reggroup
general_group, the purpose has been achieved, so this function is
no longer required.
There are two modification points here:
1. For the debugging of csky architecture, after executing "info register",
we hope to print out GPRs, PC and the registers related to exceptions.
2. With tdesc-xml, users can view the register groups described in XML.
I built GDB for all targets on a x86-64/GNU-Linux system, and
then (accidentally) passed GDB a RISC-V binary, and asked GDB to "run"
the binary on the native target. I got this error:
(gdb) show architecture
The target architecture is set to "auto" (currently "i386").
(gdb) file /tmp/hello.rv32.exe
Reading symbols from /tmp/hello.rv32.exe...
(gdb) show architecture
The target architecture is set to "auto" (currently "riscv:rv32").
(gdb) run
Starting program: /tmp/hello.rv32.exe
../../src/gdb/i387-tdep.c:596: internal-error: i387_supply_fxsave: Assertion `tdep->st0_regnum >= I386_ST0_REGNUM' failed.
What's going on here is this; initially the architecture is i386, this
is based on the default architecture, which is set based on the native
target. After loading the RISC-V executable the architecture of the
current inferior is updated based on the architecture of the
executable.
When we "run", GDB does a fork & exec, with the inferior being
controlled through ptrace. GDB sees an initial stop from the inferior
as soon as the inferior comes to life. In response to this stop GDB
ends up calling save_stop_reason (linux-nat.c), which ends up trying
to read register from the inferior, to do this we end up calling
target_ops::fetch_registers, which, for the x86-64 native target,
calls amd64_linux_nat_target::fetch_registers.
After this I eventually end up in i387_supply_fxsave, different x86
based targets will end in different functions to fetch registers, but
it doesn't really matter which function we end up in, the problem is
this line, which is repeated in many places:
i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (arch);
The problem here is that the ARCH in this line comes from the current
inferior, which, as we discussed above, will be a RISC-V gdbarch, the
tdep field will actually be of type riscv_gdbarch_tdep, not
i386_gdbarch_tdep. After this cast we are relying on undefined
behaviour, in my case I happen to trigger an assert, but this might
not always be the case.
The thing I tried that exposed this problem was of course, trying to
start an executable of the wrong architecture on a native target. I
don't think that the correct solution for this problem is to detect,
at the point of cast, that the gdbarch_tdep object is of the wrong
type, but, I did wonder, is there a way that we could protect
ourselves from incorrectly casting the gdbarch_tdep object?
I think that there is something we can do here, and this commit is the
first step in that direction, though no actual check is added by this
commit.
This commit can be split into two parts:
(1) In gdbarch.h and arch-utils.c. In these files I have modified
gdbarch_tdep (the function) so that it now takes a template argument,
like this:
template<typename TDepType>
static inline TDepType *
gdbarch_tdep (struct gdbarch *gdbarch)
{
struct gdbarch_tdep *tdep = gdbarch_tdep_1 (gdbarch);
return static_cast<TDepType *> (tdep);
}
After this change we are no better protected, but the cast is now
done within the gdbarch_tdep function rather than at the call sites,
this leads to the second, much larger change in this commit,
(2) Everywhere gdbarch_tdep is called, we make changes like this:
- i386_gdbarch_tdep *tdep = (i386_gdbarch_tdep *) gdbarch_tdep (arch);
+ i386_gdbarch_tdep *tdep = gdbarch_tdep<i386_gdbarch_tdep> (arch);
There should be no functional change after this commit.
In the next commit I will build on this change to add an assertion in
gdbarch_tdep that checks we are casting to the correct type.
For csky arch, the correspondence between Dwarf registers and GDB
registers are as follows:
dwarf regnos 0~31 ==> gdb regs r0~r31
dwarf regno CSKY_HI_REGNUM(36) ==> gdb reg hi
dwarf regno CSKY_LO_REGNUM(37) ==> gdb reg hi
dwarf regno CSKY_PC_REGNUM(72) ==> gdb reg pc
dwarf regnos FV_PSEUDO_REGNO_FIRST(74)~FV_PSEUDO_REGNO_LAST(201)
==>
gdb regs s0~s127 (pseudo regs for float and vector regs)
other dwarf regnos have no corresponding gdb regs to them.
In the existing CSKY architecture, there are at most 32 floating
and 16 vector registers. Float registers's count can be configured
as 16 or 32. In the future, the vector registers's count may be
extended to 32.
The bit width of floating-point register is 64bits, and the bit
width of vector register is 128bit.
Special points: in fr0~fr15 and vr0~vr15, each FRx is the lower
64 bits of the corresponding VRx.
Here, we will split each floating-point and vector register to
32bits wide, add the corresponding pseudo registers, and finally
use them for the dwarf registers.
There are 128 pseudo registers in total, s0~s127, including:
1. s0 and s1 correspond to fr0, s4 and s5 correspond to fr1, and so on.
Every two separated pseudo registers correspond to a float register.
2. s0, s1, s2 and s3 correspond to vr0; s4, s5, s6 and s7 correspond to vr1,
and so on. Every four pseudo registers corresponds to a vector register.
Therefore, in s64~s127, there are general registers that are not actually
used. This part is to prepare for the expansion of vector registers to 32
Therefore, in s64~s127, half of the registers are actually unused. This
part is to prepare for the expansion of the vector register to 32.
Registers in CSKY architecture included:
1. 32 gprs
2. 16 ars (alternative gprs used for quick interrupt)
3. hi, lo, pc
4. fr0~fr31, fcsr, fid, fesr
5. vr0~vr15
6. ((32 banks) * 32) cr regs (max 32 banks, 32 control regs a bank)
For register names:
Except over control registers, other registers, like gprs, hi, lo ...
are fixed names. Among the 32*32 control registers, some used registers
will have fixed names, others will have a default name "cpxcry". 'x'
refers to bank, y refers index in the bank(a control register in bank
4 with index 14 will has a default name cp4cr14).
For register numbers in GDB:
We assign a fixed number to each register in GDB, like:
r0~r31 with 0~31
hi, lo with 36, 37
fpu/vpu with 40~71
...
described in function csky_get_supported_register_by_index().
Function csky_get_supported_tdesc_registers_count():
To calculate the total number of registers that GDB can analyze,
including those with fixed names and those with default register names.
Function csky_get_supported_register_by_index():
To find a supported struct csky_supported_tdesc_register, return a
struct include name with regnum via index.
Arrays csky_supported_tdesc_feature_names[]:
Include all supported feature names in tdesc-xmls.
We use the information described above to load the register description
file of the target from the stub. When loading, do a little check that
whether the register description file contains SP, LR and PC.
First, add three variables fpu_abi, fpu_hardfp and vdsp_version
to csky_gdbarch_tdep. They will be initialized from info.abfd in
cskg_gdbarch_init.
Now, they are just used to find a candidate among the list of pre-declared
architectures
Later, they will be used in gdbarch_return_value and gdbarch_push_dummy_call
for funtions described below:
fpu_abi: to check if the bfd is using VAL_CSKY_FPU_ABI_HARD or
VAL_CSKY_FPU_ABI_SOFT
fpu_hardfp: to check if the bfd is using VAL_CSKY_FPU_HARDFP_SINGLE
or VAL_CSKY_FPU_HARDFP_DOUBLE
vdsp_version: to check if a function is returned with CSKY_VRET_REGNUM
Convert the reggroup_new and reggroup_gdbarch_new functions to return
a 'const regggroup *', and fix up all the fallout.
There should be no user visible changes after this commit.
There's a set of 7 default register groups. If we don't add any
gdbarch specific register groups during gdbarch initialisation, then
when we iterate over the register groups using reggroup_next and
reggroup_prev we will make use of these 7 default groups. See the use
of default_groups in gdb/reggroups.c for details on this.
However, if the gdbarch adds its own groups during gdbarch
initialisation, then these groups will be used in preference to the
default groups.
A problem arises though if the particular architecture makes use of
the target description mechanism. If the default target
description(s) (i.e. those internal to GDB that are used when the user
doesn't provide their own) don't mention any additional register
groups then the default register groups will be used.
But if the target description does mention additional groups then the
default groups are not used, and instead, the groups from the target
description are used.
The problem with this is that what usually happens is that the target
description will mention additional groups, e.g. groups for special
registers. Most architectures that use target descriptions work
around this by adding all (or most) of the default register groups in
all cases. See i386_add_reggroups, aarch64_add_reggroups,
riscv_add_reggroups, xtensa_add_reggroups, and others.
In this patch, my suggestion is that we should just add the default
register groups for every architecture, always. This change is in
gdb/reggroups.c.
All the remaining changes are me updating the various architectures to
not add the default groups themselves.
So, where will this change be visible to the user? I think the
following commands will possibly change:
* info registers / info all-registers:
The user can provide a register group to these commands. For example,
on csky, we previously never added the 'vector' group. Now, as a
default group, this will be available, but (presumably) will not
contain any registers. I don't think this is necessarily a bad
thing, there's something to be said for having some consistent
defaults available. There are other architectures that didn't add
all 7 of the defaults, which will now have gained additional groups.
* maint print reggroups
This prints the set of all available groups. As a maintenance
command I'm less concerned with the output changing here.
Obviously, for the architectures that didn't previously add all the
defaults, this list just got bigger.
* maint print register-groups
This prints all the registers, and the groups they are in. If the
defaults were not previously being added then a register (obviously)
can't appear in one of the default groups. Now the groups are
available then registers might be in more groups than previously.
However, this is again a maintenance command, so I'm less concerned
about this changing.
Change gdbarch_register_reggroup_p to take a 'const struct reggroup *'
argument. This requires a change to the gdb/gdbarch-components.py
script, regeneration of gdbarch.{c,h}, and then updates to all the
architectures that implement this method.
There should be no user visible changes after this commit.
Now that filtered and unfiltered output can be treated identically, we
can unify the printf family of functions. This is done under the name
"gdb_printf". Most of this patch was written by script.
I found a couple of spots that declare a symtab_and_line but don't
actually use it. I think this probably isn't detected as unused
because it has a constructor.
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.
Fix these, seen when building with clang 14:
CXX csky-tdep.o
/home/simark/src/binutils-gdb/gdb/csky-tdep.c:332:7: error: variable 'need_dummy_stack' set but not used [-Werror,-Wunused-but-set-variable]
int need_dummy_stack = 0;
^
/home/simark/src/binutils-gdb/gdb/csky-tdep.c:805:12: error: variable 'offset' set but not used [-Werror,-Wunused-but-set-variable]
int offset = 0;
^
Change-Id: I6703bcb50e83c50083f716f4084ef6aa30d659c4
I would like to be able to use non-trivial types in gdbarch_tdep types.
This is not possible at the moment (in theory), because of the one
definition rule.
To allow it, rename all gdbarch_tdep types to <arch>_gdbarch_tdep, and
make them inherit from a gdbarch_tdep base class. The inheritance is
necessary to be able to pass pointers to all these <arch>_gdbarch_tdep
objects to gdbarch_alloc, which takes a pointer to gdbarch_tdep.
These objects are never deleted through a base class pointer, so I
didn't include a virtual destructor. In the future, if gdbarch objects
deletable, I could imagine that the gdbarch_tdep objects could become
owned by the gdbarch objects, and then it would become useful to have a
virtual destructor (so that the gdbarch object can delete the owned
gdbarch_tdep object). But that's not necessary right now.
It turns out that RISC-V already has a gdbarch_tdep that is
non-default-constructible, so that provides a good motivation for this
change.
Most changes are fairly straightforward, mostly needing to add some
casts all over the place. There is however the xtensa architecture,
doing its own little weird thing to define its gdbarch_tdep. I did my
best to adapt it, but I can't test those changes.
Change-Id: Ic001903f91ddd106bd6ca09a79dabe8df2d69f3b
The bug fixed by this [1] patch was caused by an out-of-bounds access to
a value's content. The code gets the value's content (just a pointer)
and then indexes it with a non-sensical index.
This made me think of changing functions that return value contents to
return array_views instead of a plain pointer. This has the advantage
that when GDB is built with _GLIBCXX_DEBUG, accesses to the array_view
are checked, making bugs more apparent / easier to find.
This patch changes the return types of these functions, and updates
callers to call .data() on the result, meaning it's not changing
anything in practice. Additional work will be needed (which can be done
little by little) to make callers propagate the use of array_view and
reap the benefits.
[1] https://sourceware.org/pipermail/gdb-patches/2021-September/182306.html
Change-Id: I5151f888f169e1c36abe2cbc57620110673816f3
As CSKY arch has not parsed target-description.xml in csky_gdbarch_init,
when a remote server, like csky-qemu or gdbserver, send a target-description.xml
to gdb, tdesc_has_registers will return ture, but tdesc_register_name (gdbarch, 0)
will return NULL, so a cmd "info registers r0" will not work.
Function of parsing target-description.xml will be add later for CSKY arch,
now it is temporarily removed to allow me to do other supported tests.
2021-07-15 Jiangshuai Li <jiangshuai_li@c-sky.com>
* csky-tdep.c : not using tdesc funtions in csky_register_name
I wrote this while debugging a problem where the expected unwinder for a
frame wasn't used. It adds messages to show which unwinders are
considered for a frame, why they are not selected (if an exception is
thrown), and finally which unwinder is selected in the end.
To be able to show a meaningful, human-readable name for the unwinders,
add a "name" field to struct frame_unwind, and update all instances to
include a name.
Here's an example of the output:
[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"
[frame] frame_unwind_try_unwinder: no
[frame] frame_unwind_try_unwinder: trying unwinder "amd64 epilogue"
[frame] frame_unwind_try_unwinder: no
[frame] frame_unwind_try_unwinder: trying unwinder "i386 epilogue"
[frame] frame_unwind_try_unwinder: no
[frame] frame_unwind_try_unwinder: trying unwinder "dwarf2"
[frame] frame_unwind_try_unwinder: yes
gdb/ChangeLog:
* frame-unwind.h (struct frame_unwind) <name>: New. Update
instances everywhere to include this field.
* frame-unwind.c (frame_unwind_try_unwinder,
frame_unwind_find_by_frame): Add debug messages.
Change-Id: I813f17777422425f0d08b22499817b23922e8ddb
