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>
This replaces frame_id_eq with operator== and operator!=. I wrote
this for a version of this series that I later abandoned; but since it
simplifies the code, I left this patch in.
Approved-by: Tom Tomey <tom@tromey.com>
gdbarch implements its own registry-like approach. This patch changes
it to instead use registry.h. It's a rather large patch but largely
uninteresting -- it's mostly a straightforward conversion from the old
approach to the new one.
The main benefit of this change is that it introduces type safety to
the gdbarch registry. It also removes a bunch of code.
One possible drawback is that, previously, the gdbarch registry
differentiated between pre- and post-initialization setup. This
doesn't seem very important to me, though.
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.
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
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
The following patch drops the overloading going on with the trad_frame_saved_reg
struct and defines a new struct with a KIND enum and a union of different
fields.
The new struct looks like this:
struct trad_frame_saved_reg
{
setters/getters
...
private:
trad_frame_saved_reg_kind m_kind;
union {
LONGEST value;
int realreg;
LONGEST addr;
const gdb_byte *value_bytes;
} m_reg;
};
And the enums look like this:
/* Describes the kind of encoding a stored register has. */
enum class trad_frame_saved_reg_kind
{
/* Register value is unknown. */
UNKNOWN = 0,
/* Register value is a constant. */
VALUE,
/* Register value is in another register. */
REALREG,
/* Register value is at an address. */
ADDR,
/* Register value is a sequence of bytes. */
VALUE_BYTES
};
The patch also adds setters/getters and updates all the users of the old
struct.
It is worth mentioning that due to the previous overloaded nature of the
fields, some tdep files like to store negative offsets and indexes in the ADDR
field, so I kept the ADDR as LONGEST instead of CORE_ADDR. Those cases may
be better supported by a new enum entry.
I have not addressed those cases in this patch to prevent unwanted breakage,
given I have no way to test some of the targets. But it would be nice to
clean those up eventually.
The change to frame-unwind.* is to constify the parameter being passed to the
unwinding functions, given we now accept a "const gdb_byte *" for value bytes.
Tested on aarch64-linux/Ubuntu 20.04/18.04 and by building GDB with
--enable-targets=all.
gdb/ChangeLog:
2021-01-04 Luis Machado <luis.machado@linaro.org>
Update all users of trad_frame_saved_reg to use the new member
functions.
Remote all struct keywords from declarations of trad_frame_saved_reg
types, except on forward declarations.
* aarch64-tdep.c: Update.
* alpha-mdebug-tdep.c: Update.
* alpha-tdep.c: Update.
* arc-tdep.c: Update.
* arm-tdep.c: Update.
* avr-tdep.c: Update.
* cris-tdep.c: Update.
* csky-tdep.c: Update.
* frv-tdep.c: Update.
* hppa-linux-tdep.c: Update.
* hppa-tdep.c: Update.
* hppa-tdep.h: Update.
* lm32-tdep.c: Update.
* m32r-linux-tdep.c: Update.
* m32r-tdep.c: Update.
* m68hc11-tdep.c: Update.
* mips-tdep.c: Update.
* moxie-tdep.c: Update.
* riscv-tdep.c: Update.
* rs6000-tdep.c: Update.
* s390-linux-tdep.c: Update.
* s390-tdep.c: Update.
* score-tdep.c: Update.
* sparc-netbsd-tdep.c: Update.
* sparc-sol2-tdep.c: Update.
* sparc64-fbsd-tdep.c: Update.
* sparc64-netbsd-tdep.c: Update.
* sparc64-obsd-tdep.c: Update.
* sparc64-sol2-tdep.c: Update.
* tilegx-tdep.c: Update.
* v850-tdep.c: Update.
* vax-tdep.c: Update.
* frame-unwind.c (frame_unwind_got_bytes): Make parameter const.
* frame-unwind.h (frame_unwind_got_bytes): Likewise.
* trad-frame.c: Update.
Remove TF_REG_* enum.
(trad_frame_alloc_saved_regs): Add a static assertion to check for
a trivially-constructible struct.
(trad_frame_reset_saved_regs): Adjust to use member function.
(trad_frame_value_p): Likewise.
(trad_frame_addr_p): Likewise.
(trad_frame_realreg_p): Likewise.
(trad_frame_value_bytes_p): Likewise.
(trad_frame_set_value): Likewise.
(trad_frame_set_realreg): Likewise.
(trad_frame_set_addr): Likewise.
(trad_frame_set_unknown): Likewise.
(trad_frame_set_value_bytes): Likewise.
(trad_frame_get_prev_register): Likewise.
* trad-frame.h: Update.
(trad_frame_saved_reg_kind): New enum.
(struct trad_frame_saved_reg) <addr, realreg, data>: Remove.
<m_kind, m_reg>: New member fields.
<set_value, set_realreg, set_addr, set_unknown, set_value_bytes>
<kind, value, realreg, addr, value_bytes, is_value, is_realreg>
<is_addr, is_unknown, is_value_bytes>: New member functions.
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.
TLDR: frame_unwind_got_optimized uses wrong frame id value, trying to
fix it makes GDB sad, return not_lval value and don't use frame id value
instead.
Longer version:
The `prev_register` method of the `frame_unwind` interface corresponds
to asking the question: "where did this frame - passed as a parameter -
save the value this register had in its caller frame?". When "this
frame" did not save that register value (DW_CFA_undefined in DWARF), the
implementation can use the `frame_unwind_got_optimized` function to
create a struct value that represents the optimized out / not saved
register.
`frame_unwind_got_optimized` marks the value as fully optimized out,
sets the lval field to lval_register and assigns the required data for
lval_register: the next frame id and the register number. The problem
is that it uses the frame id from the wrong frame (see below for in
depth explanation). In practice, this is not problematic because the
frame id is never used: the value is already not lazy (and is marked as
optimized out), so the value is never fetched from the target.
When trying to change it to put the right next frame id in the value, we
bump into problems: computing the frame id for some frame requires
unwinding some register, if that register is not saved / optimized out,
we try to get the frame id that we are currently computing.
This patch addresses the problem by changing
`frame_unwind_got_optimized` to return a not_lval value instead. Doing
so, we don't need to put a frame id, so we don't hit that problem. It
may seem like an unnecessary change today, because it looks like we're
fixing something that is not broken (from the user point of view).
However, the bug becomes user visible with the following patches, where
inline frames are involved. I put this change in its own patch to keep
it logically separate.
Let's now illustrate how we are putting the wrong frame id in the value
returned by `frame_unwind_got_optimized`. Let's assume this stack:
frame #0
frame #1
frame #2
frame #3
Let's suppose that we are calling `frame_unwind_register_value` with
frame #2 as the "next_frame" parameter and some register number X as the
regnum parameter. That is like asking the question "where did frame #2
save frame #3's value for register X".
`frame_unwind_register_value` calls the frame unwinder's `prev_register`
method, which in our case is `dwarf2_frame_prev_register`. Note that in
`dwarf2_frame_prev_register`, the parameter is now called `this_frame`,
but its value is still frame #2, and we are still looking for where
frame #2 saved frame #3's value of register X.
Let's now suppose that frame #2's CFI explicitly indicates that the
register X is was not saved (DW_CFA_undefined). We go into
`frame_unwind_got_optimized`.
In `frame_unwind_got_optimized`, the intent is to create a value that
represents register X in frame #3. An lval_register value requires that
we specify the id of the _next_ frame, that is the frame from which we
would need to unwind in order to get the value. Therefore, we would
want to put the id of frame #2 in there.
However, `frame_unwind_got_optimized` does:
VALUE_NEXT_FRAME_ID (val)
= get_frame_id (get_next_frame_sentinel_okay (frame));
where `frame` is frame #2. The get_next_frame_sentinel_okay call
returns frame #1, so we end up putting frame #1's id in the value.
Let's now pretend that we try to "fix" it by placing the right frame id,
in other words doing this change:
--- a/gdb/frame-unwind.c
+++ b/gdb/frame-unwind.c
@@ -260,8 +260,7 @@ frame_unwind_got_optimized (struct frame_info *frame, int regnum)
mark_value_bytes_optimized_out (val, 0, TYPE_LENGTH (type));
VALUE_LVAL (val) = lval_register;
VALUE_REGNUM (val) = regnum;
- VALUE_NEXT_FRAME_ID (val)
- = get_frame_id (get_next_frame_sentinel_okay (frame));
+ VALUE_NEXT_FRAME_ID (val) = get_frame_id (frame);
return val;
}
This makes some tests fails, such as gdb.dwarf2/dw2-undefined-ret-addr.exp,
like so:
...
#9 0x0000557a8ab15a5d in internal_error (file=0x557a8b31ef80 "/home/simark/src/binutils-gdb/gdb/frame.c", line=623, fmt=0x557a8b31efe0 "%s: Assertion `%s' failed.") at /home/simark/src/binutils-gdb/gdbsupport/errors.cc:55
#10 0x0000557a87f816d6 in get_frame_id (fi=0x62100034bde0) at /home/simark/src/binutils-gdb/gdb/frame.c:623
#11 0x0000557a87f7cac7 in frame_unwind_got_optimized (frame=0x62100034bde0, regnum=16) at /home/simark/src/binutils-gdb/gdb/frame-unwind.c:264
#12 0x0000557a87a71a76 in dwarf2_frame_prev_register (this_frame=0x62100034bde0, this_cache=0x62100034bdf8, regnum=16) at /home/simark/src/binutils-gdb/gdb/dwarf2/frame.c:1267
#13 0x0000557a87f86621 in frame_unwind_register_value (next_frame=0x62100034bde0, regnum=16) at /home/simark/src/binutils-gdb/gdb/frame.c:1288
#14 0x0000557a87f855d5 in frame_register_unwind (next_frame=0x62100034bde0, regnum=16, optimizedp=0x7fff5f459070, unavailablep=0x7fff5f459080, lvalp=0x7fff5f4590a0, addrp=0x7fff5f4590b0, realnump=0x7fff5f459090, bufferp=0x7fff5f459150 "") at /home/simark/src/binutils-gdb/gdb/frame.c:1191
#15 0x0000557a87f860ef in frame_unwind_register (next_frame=0x62100034bde0, regnum=16, buf=0x7fff5f459150 "") at /home/simark/src/binutils-gdb/gdb/frame.c:1247
#16 0x0000557a881875f9 in i386_unwind_pc (gdbarch=0x621000190110, next_frame=0x62100034bde0) at /home/simark/src/binutils-gdb/gdb/i386-tdep.c:1971
#17 0x0000557a87fe58a5 in gdbarch_unwind_pc (gdbarch=0x621000190110, next_frame=0x62100034bde0) at /home/simark/src/binutils-gdb/gdb/gdbarch.c:3062
#18 0x0000557a87a6267b in dwarf2_tailcall_sniffer_first (this_frame=0x62100034bde0, tailcall_cachep=0x62100034bee0, entry_cfa_sp_offsetp=0x7fff5f4593f0) at /home/simark/src/binutils-gdb/gdb/dwarf2/frame-tailcall.c:387
#19 0x0000557a87a70cdf in dwarf2_frame_cache (this_frame=0x62100034bde0, this_cache=0x62100034bdf8) at /home/simark/src/binutils-gdb/gdb/dwarf2/frame.c:1198
#20 0x0000557a87a711c2 in dwarf2_frame_this_id (this_frame=0x62100034bde0, this_cache=0x62100034bdf8, this_id=0x62100034be40) at /home/simark/src/binutils-gdb/gdb/dwarf2/frame.c:1226
#21 0x0000557a87f81167 in compute_frame_id (fi=0x62100034bde0) at /home/simark/src/binutils-gdb/gdb/frame.c:587
#22 0x0000557a87f81803 in get_frame_id (fi=0x62100034bde0) at /home/simark/src/binutils-gdb/gdb/frame.c:635
#23 0x0000557a87f7efef in scoped_restore_selected_frame::scoped_restore_selected_frame (this=0x7fff5f459920) at /home/simark/src/binutils-gdb/gdb/frame.c:320
#24 0x0000557a891488ae in print_frame_args (fp_opts=..., func=0x621000183b90, frame=0x62100034bde0, num=-1, stream=0x6030000caa20) at /home/simark/src/binutils-gdb/gdb/stack.c:750
#25 0x0000557a8914e87a in print_frame (fp_opts=..., frame=0x62100034bde0, print_level=0, print_what=SRC_AND_LOC, print_args=1, sal=...) at /home/simark/src/binutils-gdb/gdb/stack.c:1394
#26 0x0000557a8914c2ae in print_frame_info (fp_opts=..., frame=0x62100034bde0, print_level=0, print_what=SRC_AND_LOC, print_args=1, set_current_sal=1) at /home/simark/src/binutils-gdb/gdb/stack.c:1119
...
We end up calling get_frame_id (in the hunk above, frame #10) while we are
computing it (frame #21), and that's not good.
Now, the question is how do we fix this. I suggest making the unwinder
return a not_lval value in this case.
The reason why we return an lval_register here is to make sure that this
is printed as "not saved" and not "optimized out" down the line. See
these two commits:
1. 901461f8eb ("Print registers not saved in the frame as "<not saved>"
instead of "<optimized out>".").
2. 6bd273ae45 ("Make "set debug frame 1" output print <not saved> instead of
<optimized out>.")
The current design (introduced by the first commit) is to check the
value's lval to choose which one to print (see val_print_optimized_out).
Making the unwinder return not_lval instead of lval_register doesn't
break "not saved" when doing "print $rax" or "info registers", because
value_fetch_lazy_register only consumes the contents and optimized-out
property from the value the unwinder returned. The value being
un-lazified stays an lval_register.
I believe that this is a correct technical solution (and not just
papering over the problem), because what we expect of unwinders is to
tell us where a given register's value is saved. If the value is saved
in memory, -> lval_memory. If the value is saved in some other register
of the next frame, -> lval_register. If the value is not saved, it
doesn't really make sense to return an lval_register value. not_lval
would be more appropriate. If the code then wants to represent an
optimized out register value (like value_fetch_lazy_register does), then
it's a separate concern which shouldn't involve the unwinder.
This change breaks the output of "set debug frame 1" though (introduced
by the second commit), since that logging statement consumes the return
value of the unwinder directly. To keep the correct behavior, just make
`frame_unwind_register_value` call `val_print_not_saved` directly,
instead of `val_print_optimized_out`. This is fine because we know in
this context that we are always talking about a register value, and that
we want to show "not saved" for those.
I augmented the gdb.dwarf2/dw2-reg-undefined.exp test case to test some
cases I stumbled on while working on this, which I think are not tested
anywhere:
- the "set debug frame 1" debug output mentioned above. It's just debug
output, but if we want to make sure it doesn't change, it should be
tested
- printing not-saved register values from the history (should print not
saved)
- copying a not-saved register value in a convenience variable. In this
case, we expect that printing the convenience variable shows
"optimized out", because we copied the value, not the property of
where the value came from.
gdb/ChangeLog:
* frame-unwind.c (frame_unwind_got_optimized): Don't set
regnum/frame in value. Call allocate_value_lazy.
* frame.c (frame_unwind_register_value): Use
val_print_not_saved.
gdb/testsuite/ChangeLog:
* gdb.dwarf2/dw2-reg-undefined.exp: Test "set debug frame 1"
output, printing a "not saved" value from history and printing a
convenience variable created from a "not saved" value.
Change-Id: If451739a3ef7a5b453b1f50707e21ce16d74807e
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.
A customer reported a failure to unwind in a certain core dump. A
lengthy investigation showed that the problem came from the
interaction between the tailcall and inline frame sniffers.
Normally, the regular DWARF unwinder may discover a chain of tail
calls ending in the current frame. In this case, it sets a member on
the dwarf2_frame_cache object, so that a subsequent call into the
tailcall sniffer will create the tailcall frames.
However, in this scenario, what happened is that the DWARF unwinder
did find tailcall frames -- but then the PC of the first such frame
was recognized and claimed by the inline frame sniffer.
This then caused unwinding to go astray further up the stack.
This patch fixes the problem by arranging for the tailcall sniffer to
be called before the inline sniffer. This way, if a DWARF frame has
tailcall information, the tailcalls will always be processed first.
This is safe to do, because the tailcall sniffer can only claim a
frame if the previous frame did in fact find this information. (So,
for example, if no DWARF frame is ever found, then this sniffer will
never trigger.)
This patch also partially reverts:
commit 1ec56e88aa
Author: Pedro Alves <palves@redhat.com>
Date: Fri Nov 22 13:17:46 2013 +0000
Eliminate dwarf2_frame_cache recursion, don't unwind from the dwarf2 sniffer (move dwarf2_tailcall_sniffer_first elsewhere).
That patch moved the call to dwarf2_tailcall_sniffer_first out of
dwarf2_frame_cache, and into dwarf2_frame_prev_register. However, in
this situation, this is too late -- by the time
dwarf2_frame_prev_register is called, the frame in question is already
recognized by the inline frame sniffer.
Rather than fully revert that patch, though, this just arranges to
call dwarf2_tailcall_sniffer_first from dwarf2_frame_cache -- which is
called shortly after the DWARF frame sniffer succeeds, via
compute_frame_id.
I don't know how to write a test case for this.
gdb/ChangeLog
2020-03-03 Tom Tromey <tromey@adacore.com>
* dwarf2/frame.c (struct dwarf2_frame_cache)
<checked_tailcall_bottom, entry_cfa_sp_offset,
entry_cfa_sp_offset_p>: Remove members.
(dwarf2_frame_cache): Call dwarf2_tailcall_sniffer_first.
(dwarf2_frame_prev_register): Don't call
dwarf2_tailcall_sniffer_first.
(dwarf2_append_unwinders): Don't append tailcall unwinder.
* frame-unwind.c (add_unwinder): New fuction.
(frame_unwind_init): Use it. Add tailcall unwinder.
I touched symtab.h and was surprised to see how many files were
rebuilt. I looked into it a bit, and found that defs.h includes
gdbarch.h, which in turn includes many things.
gdbarch.h is only needed by a minority ofthe files in gdb, so this
patch removes the include from defs.h and updates the fallout.
I did "wc -l" on the files in build/gdb/.deps; this patch reduces the
line count from 139935 to 137030; so there are definitely future
build-time savings here.
Note that while I configured with --enable-targets=all, it's possible
that some *-nat.c file needs an update. I could not test all of
these. The buildbot caught a few problems along these lines.
gdb/ChangeLog
2019-07-10 Tom Tromey <tom@tromey.com>
* defs.h: Don't include gdbarch.h.
* aarch64-ravenscar-thread.c, aarch64-tdep.c, alpha-bsd-tdep.h,
alpha-linux-tdep.c, alpha-mdebug-tdep.c, arch-utils.h, arm-tdep.h,
ax-general.c, btrace.c, buildsym-legacy.c, buildsym.h, c-lang.c,
cli/cli-decode.h, cli/cli-dump.c, cli/cli-script.h,
cli/cli-style.h, coff-pe-read.h, compile/compile-c-support.c,
compile/compile-cplus.h, compile/compile-loc2c.c, corefile.c,
cp-valprint.c, cris-linux-tdep.c, ctf.c, d-lang.c, d-namespace.c,
dcache.c, dicos-tdep.c, dictionary.c, disasm-selftests.c,
dummy-frame.c, dummy-frame.h, dwarf2-frame-tailcall.c,
dwarf2expr.c, expression.h, f-lang.c, frame-base.c,
frame-unwind.c, frv-linux-tdep.c, gdbarch-selftests.c, gdbtypes.h,
go-lang.c, hppa-nbsd-tdep.c, hppa-obsd-tdep.c, i386-dicos-tdep.c,
i386-tdep.h, ia64-vms-tdep.c, interps.h, language.c,
linux-record.c, location.h, m2-lang.c, m32r-linux-tdep.c,
mem-break.c, memattr.c, mn10300-linux-tdep.c, nios2-linux-tdep.c,
objfiles.h, opencl-lang.c, or1k-linux-tdep.c, p-lang.c,
parser-defs.h, ppc-tdep.h, probe.h, python/py-record-btrace.c,
record-btrace.c, record.h, regcache-dump.c, regcache.h,
riscv-fbsd-tdep.c, riscv-linux-tdep.c, rust-exp.y,
sh-linux-tdep.c, sh-nbsd-tdep.c, source-cache.c,
sparc-nbsd-tdep.c, sparc-obsd-tdep.c, sparc-ravenscar-thread.c,
sparc64-fbsd-tdep.c, std-regs.c, target-descriptions.h,
target-float.c, tic6x-linux-tdep.c, tilegx-linux-tdep.c, top.c,
tracefile.c, trad-frame.c, type-stack.h, ui-style.c, utils.c,
utils.h, valarith.c, valprint.c, varobj.c, x86-tdep.c,
xml-support.h, xtensa-linux-tdep.c, cli/cli-cmds.h: Update.
* s390-linux-nat.c, procfs.c, inf-ptrace.c: Likewise.
This rewrites gdb's TRY/CATCH to plain C++ try/catch. The patch was
largely written by script, though one change (to a comment in
common-exceptions.h) was reverted by hand.
gdb/ChangeLog
2019-04-08 Tom Tromey <tom@tromey.com>
* xml-support.c: Use C++ exception handling.
* x86-linux-nat.c: Use C++ exception handling.
* windows-nat.c: Use C++ exception handling.
* varobj.c: Use C++ exception handling.
* value.c: Use C++ exception handling.
* valprint.c: Use C++ exception handling.
* valops.c: Use C++ exception handling.
* unittests/parse-connection-spec-selftests.c: Use C++ exception
handling.
* unittests/cli-utils-selftests.c: Use C++ exception handling.
* typeprint.c: Use C++ exception handling.
* tui/tui.c: Use C++ exception handling.
* tracefile-tfile.c: Use C++ exception handling.
* top.c: Use C++ exception handling.
* thread.c: Use C++ exception handling.
* target.c: Use C++ exception handling.
* symmisc.c: Use C++ exception handling.
* symfile-mem.c: Use C++ exception handling.
* stack.c: Use C++ exception handling.
* sparc64-linux-tdep.c: Use C++ exception handling.
* solib.c: Use C++ exception handling.
* solib-svr4.c: Use C++ exception handling.
* solib-spu.c: Use C++ exception handling.
* solib-frv.c: Use C++ exception handling.
* solib-dsbt.c: Use C++ exception handling.
* selftest-arch.c: Use C++ exception handling.
* s390-tdep.c: Use C++ exception handling.
* rust-lang.c: Use C++ exception handling.
* rust-exp.y: Use C++ exception handling.
* rs6000-tdep.c: Use C++ exception handling.
* rs6000-aix-tdep.c: Use C++ exception handling.
* riscv-tdep.c: Use C++ exception handling.
* remote.c: Use C++ exception handling.
* remote-fileio.c: Use C++ exception handling.
* record-full.c: Use C++ exception handling.
* record-btrace.c: Use C++ exception handling.
* python/python.c: Use C++ exception handling.
* python/py-value.c: Use C++ exception handling.
* python/py-utils.c: Use C++ exception handling.
* python/py-unwind.c: Use C++ exception handling.
* python/py-type.c: Use C++ exception handling.
* python/py-symbol.c: Use C++ exception handling.
* python/py-record.c: Use C++ exception handling.
* python/py-record-btrace.c: Use C++ exception handling.
* python/py-progspace.c: Use C++ exception handling.
* python/py-prettyprint.c: Use C++ exception handling.
* python/py-param.c: Use C++ exception handling.
* python/py-objfile.c: Use C++ exception handling.
* python/py-linetable.c: Use C++ exception handling.
* python/py-lazy-string.c: Use C++ exception handling.
* python/py-infthread.c: Use C++ exception handling.
* python/py-inferior.c: Use C++ exception handling.
* python/py-gdb-readline.c: Use C++ exception handling.
* python/py-framefilter.c: Use C++ exception handling.
* python/py-frame.c: Use C++ exception handling.
* python/py-finishbreakpoint.c: Use C++ exception handling.
* python/py-cmd.c: Use C++ exception handling.
* python/py-breakpoint.c: Use C++ exception handling.
* python/py-arch.c: Use C++ exception handling.
* printcmd.c: Use C++ exception handling.
* ppc-linux-tdep.c: Use C++ exception handling.
* parse.c: Use C++ exception handling.
* p-valprint.c: Use C++ exception handling.
* objc-lang.c: Use C++ exception handling.
* mi/mi-main.c: Use C++ exception handling.
* mi/mi-interp.c: Use C++ exception handling.
* mi/mi-cmd-stack.c: Use C++ exception handling.
* mi/mi-cmd-break.c: Use C++ exception handling.
* main.c: Use C++ exception handling.
* linux-thread-db.c: Use C++ exception handling.
* linux-tdep.c: Use C++ exception handling.
* linux-nat.c: Use C++ exception handling.
* linux-fork.c: Use C++ exception handling.
* linespec.c: Use C++ exception handling.
* language.c: Use C++ exception handling.
* jit.c: Use C++ exception handling.
* infrun.c: Use C++ exception handling.
* infcmd.c: Use C++ exception handling.
* infcall.c: Use C++ exception handling.
* inf-loop.c: Use C++ exception handling.
* i386-tdep.c: Use C++ exception handling.
* i386-linux-tdep.c: Use C++ exception handling.
* guile/scm-value.c: Use C++ exception handling.
* guile/scm-type.c: Use C++ exception handling.
* guile/scm-symtab.c: Use C++ exception handling.
* guile/scm-symbol.c: Use C++ exception handling.
* guile/scm-pretty-print.c: Use C++ exception handling.
* guile/scm-ports.c: Use C++ exception handling.
* guile/scm-param.c: Use C++ exception handling.
* guile/scm-math.c: Use C++ exception handling.
* guile/scm-lazy-string.c: Use C++ exception handling.
* guile/scm-frame.c: Use C++ exception handling.
* guile/scm-disasm.c: Use C++ exception handling.
* guile/scm-cmd.c: Use C++ exception handling.
* guile/scm-breakpoint.c: Use C++ exception handling.
* guile/scm-block.c: Use C++ exception handling.
* guile/guile-internal.h: Use C++ exception handling.
* gnu-v3-abi.c: Use C++ exception handling.
* gdbtypes.c: Use C++ exception handling.
* frame.c: Use C++ exception handling.
* frame-unwind.c: Use C++ exception handling.
* fbsd-tdep.c: Use C++ exception handling.
* f-valprint.c: Use C++ exception handling.
* exec.c: Use C++ exception handling.
* event-top.c: Use C++ exception handling.
* event-loop.c: Use C++ exception handling.
* eval.c: Use C++ exception handling.
* dwarf2read.c: Use C++ exception handling.
* dwarf2loc.c: Use C++ exception handling.
* dwarf2-frame.c: Use C++ exception handling.
* dwarf2-frame-tailcall.c: Use C++ exception handling.
* dwarf-index-write.c: Use C++ exception handling.
* dwarf-index-cache.c: Use C++ exception handling.
* dtrace-probe.c: Use C++ exception handling.
* disasm-selftests.c: Use C++ exception handling.
* darwin-nat.c: Use C++ exception handling.
* cp-valprint.c: Use C++ exception handling.
* cp-support.c: Use C++ exception handling.
* cp-abi.c: Use C++ exception handling.
* corelow.c: Use C++ exception handling.
* completer.c: Use C++ exception handling.
* compile/compile-object-run.c: Use C++ exception handling.
* compile/compile-object-load.c: Use C++ exception handling.
* compile/compile-cplus-symbols.c: Use C++ exception handling.
* compile/compile-c-symbols.c: Use C++ exception handling.
* common/selftest.c: Use C++ exception handling.
* common/new-op.c: Use C++ exception handling.
* cli/cli-script.c: Use C++ exception handling.
* cli/cli-interp.c: Use C++ exception handling.
* cli/cli-cmds.c: Use C++ exception handling.
* c-varobj.c: Use C++ exception handling.
* btrace.c: Use C++ exception handling.
* breakpoint.c: Use C++ exception handling.
* break-catch-throw.c: Use C++ exception handling.
* arch-utils.c: Use C++ exception handling.
* amd64-tdep.c: Use C++ exception handling.
* ada-valprint.c: Use C++ exception handling.
* ada-typeprint.c: Use C++ exception handling.
* ada-lang.c: Use C++ exception handling.
* aarch64-tdep.c: Use C++ exception handling.
gdb/gdbserver/ChangeLog
2019-04-08 Tom Tromey <tom@tromey.com>
* server.c: Use C++ exception handling.
* linux-low.c: Use C++ exception handling.
* gdbreplay.c: Use C++ exception handling.
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.
Supply default gdbarch methods for gdbarch_dummy_id,
gdbarch_unwind_pc, and gdbarch_unwind_sp. This patch doesn't actually
convert any targets to use these methods, and so, there will be no
user visible changes after this commit.
The implementations for default_dummy_id and default_unwind_sp are
fairly straight forward, these just take on the pattern used by most
targets. Once these default methods are in place then most targets
will be able to switch over.
The implementation for default_unwind_pc is also fairly straight
forward, but maybe needs some explanation.
This patch has gone through a number of iterations:
https://sourceware.org/ml/gdb-patches/2018-03/msg00165.htmlhttps://sourceware.org/ml/gdb-patches/2018-03/msg00306.htmlhttps://sourceware.org/ml/gdb-patches/2018-06/msg00090.htmlhttps://sourceware.org/ml/gdb-patches/2018-09/msg00127.html
and the implementation of default_unwind_pc has changed over this
time. Originally, I took an implementation like this:
CORE_ADDR
default_unwind_pc (struct gdbarch *gdbarch, struct frame_info *next_frame)
{
int pc_regnum = gdbarch_pc_regnum (gdbarch);
return frame_unwind_register_unsigned (next_frame, pc_regnum);
}
This is basically a clone of default_unwind_sp, but using $pc. It was
pointed out that we could potentially do better, and in version 2 the
implementation became:
CORE_ADDR
default_unwind_pc (struct gdbarch *gdbarch, struct frame_info *next_frame)
{
struct type *type;
int pc_regnum;
CORE_ADDR addr;
struct value *value;
pc_regnum = gdbarch_pc_regnum (gdbarch);
value = frame_unwind_register_value (next_frame, pc_regnum);
type = builtin_type (gdbarch)->builtin_func_ptr;
addr = extract_typed_address (value_contents_all (value), type);
addr = gdbarch_addr_bits_remove (gdbarch, addr);
release_value (value);
value_free (value);
return addr;
}
The idea was to try split out some of the steps of unwinding the $pc,
steps that are on some (or many) targets no-ops, and so allow targets
that do override these methods, to make use of default_unwind_pc.
This implementation remained in place for version 2, 3, and 4.
However, I realised that I'd made a mistake, most targets simply use
frame_unwind_register_unsigned to unwind the $pc, and this throws an
error if the register value is optimized out or unavailable. My new
proposed implementation doesn't do this, I was going to end up
breaking many targets.
I considered duplicating the code from frame_unwind_register_unsigned
that throws the errors into my new default_unwind_pc, however, this
felt really overly complex. So, what I instead went with was to
simply revert back to using frame_unwind_register_unsigned. Almost
all existing targets already use this. Some of the ones that don't can
be converted to, which means almost all targets could end up using the
default.
One addition I have made over the version 1 implementation is to add a
call to gdbarch_addr_bits_remove. For most targets this is a no-op,
but for a handful, having this call in place will mean that they can
use the default method. After all this, the new default_unwind_pc now
looks like this:
CORE_ADDR
default_unwind_pc (struct gdbarch *gdbarch, struct frame_info *next_frame)
{
int pc_regnum = gdbarch_pc_regnum (gdbarch);
CORE_ADDR pc = frame_unwind_register_unsigned (next_frame, pc_regnum);
pc = gdbarch_addr_bits_remove (gdbarch, pc);
return pc;
}
gdb/ChangeLog:
* gdb/dummy-frame.c (default_dummy_id): Defined new function.
* gdb/dummy-frame.h (default_dummy_id): Declare new function.
* gdb/frame-unwind.c (default_unwind_pc): Define new function.
(default_unwind_sp): Define new function.
* gdb/frame-unwind.h (default_unwind_pc): Declare new function.
(default_unwind_sp): Declare new function.
* gdb/frame.c (frame_unwind_pc): Assume gdbarch_unwind_pc is
available.
(get_frame_sp): Assume that gdbarch_unwind_sp is available.
* gdb/gdbarch.c: Regenerate.
* gdb/gdbarch.h: Regenerate.
* gdb/gdbarch.sh: Update definition of dummy_id, unwind_pc, and
unwind_sp. Add additional header files to be included in
generated file.
I ran into a GDB crash in gdb.base/bp-cmds-continue-ctrl-c.exp in my
multi-target branch, which turns out exposed a bug that exists in
master too.
That testcase has a breakpoint with a "continue" command associated.
Then the breakpoint is constantly being hit. At the same time, the
testcase is continualy interrupting the program with Ctrl-C, and
re-resuming it, in a loop.
Running that testcase manually under Valgrind, after a few sequences
of 'Ctrl-C' + 'continue', I got:
Breakpoint 1, Quit
(gdb) ==21270== Invalid read of size 8
==21270== at 0x4D8185: pyuw_this_id(frame_info*, void**, frame_id*) (py-unwind.c:461)
==21270== by 0x6D426A: compute_frame_id(frame_info*) (frame.c:505)
==21270== by 0x6D43B7: get_frame_id(frame_info*) (frame.c:537)
==21270== by 0x84F3B8: scoped_restore_current_thread::scoped_restore_current_thread() (thread.c:1678)
==21270== by 0x718E3D: fetch_inferior_event(void*) (infrun.c:4076)
==21270== by 0x7067C9: inferior_event_handler(inferior_event_type, void*) (inf-loop.c:43)
==21270== by 0x45BEF9: handle_target_event(int, void*) (linux-nat.c:4419)
==21270== by 0x6C4255: handle_file_event(file_handler*, int) (event-loop.c:733)
==21270== by 0x6C47F8: gdb_wait_for_event(int) (event-loop.c:859)
==21270== by 0x6C3666: gdb_do_one_event() (event-loop.c:322)
==21270== by 0x6C3712: start_event_loop() (event-loop.c:371)
==21270== by 0x746801: captured_command_loop() (main.c:329)
==21270== Address 0x0 is not stack'd, malloc'd or (recently) free'd
==21270==
==21270==
==21270== Process terminating with default action of signal 11 (SIGSEGV): dumping core
==21270== Access not within mapped region at address 0x0
==21270== at 0x4D8185: pyuw_this_id(frame_info*, void**, frame_id*) (py-unwind.c:461)
==21270== by 0x6D426A: compute_frame_id(frame_info*) (frame.c:505)
==21270== by 0x6D43B7: get_frame_id(frame_info*) (frame.c:537)
==21270== by 0x84F3B8: scoped_restore_current_thread::scoped_restore_current_thread() (thread.c:1678)
==21270== by 0x718E3D: fetch_inferior_event(void*) (infrun.c:4076)
==21270== by 0x7067C9: inferior_event_handler(inferior_event_type, void*) (inf-loop.c:43)
==21270== by 0x45BEF9: handle_target_event(int, void*) (linux-nat.c:4419)
==21270== by 0x6C4255: handle_file_event(file_handler*, int) (event-loop.c:733)
==21270== by 0x6C47F8: gdb_wait_for_event(int) (event-loop.c:859)
==21270== by 0x6C3666: gdb_do_one_event() (event-loop.c:322)
==21270== by 0x6C3712: start_event_loop() (event-loop.c:371)
==21270== by 0x746801: captured_command_loop() (main.c:329)
==21270== If you believe this happened as a result of a stack
==21270== overflow in your program's main thread (unlikely but
==21270== possible), you can try to increase the size of the
==21270== main thread stack using the --main-stacksize= flag.
==21270== The main thread stack size used in this run was 8388608.
==21270==
Above, when we get to compute_frame_id, fi->unwind is non-NULL,
meaning, we found an unwinder, in this case the Python unwinder, but
somehow, fi->prologue_cache is left NULL. pyuw_this_id then crashes
because it assumes fi->prologue_cache is non-NULL:
static void
pyuw_this_id (struct frame_info *this_frame, void **cache_ptr,
struct frame_id *this_id)
{
*this_id = ((cached_frame_info *) *cache_ptr)->frame_id;
^^^^^^^^^^
'*cache_ptr' here is 'fi->prologue_cache'.
There's a quit() call in pyuw_sniffer that I believe is the one that
sometimes triggers the crash above. The crash can be reproduced
easily with this hack to force a quit out of the python unwinder:
--- a/gdb/python/py-unwind.c
+++ b/gdb/python/py-unwind.c
@@ -497,6 +497,8 @@ pyuw_sniffer (const struct frame_unwind *self, struct frame_info *this_frame,
struct gdbarch *gdbarch = (struct gdbarch *) (self->unwind_data);
cached_frame_info *cached_frame;
+ quit ();
+
gdbpy_enter enter_py (gdbarch, current_language);
TRACE_PY_UNWIND (3, "%s (SP=%s, PC=%s)\n", __FUNCTION__,
After that quit is thrown, any subsequent operation that involves
unwinding results in GDB crashing with SIGSEGV like above.
The problem is that this commit:
commit 30a9c02fef
CommitDate: Sun Oct 8 23:16:42 2017 -0600
Subject: Remove cleanup from frame_prepare_for_sniffer
missed that we need to call frame_cleanup_after_sniffer before
rethrowing the exception too.
Without the fix, the "bt" added to
gdb.base/bp-cmds-continue-ctrl-c.exp in this commit makes GDB crash:
Running src/gdb/testsuite/gdb.base/bp-cmds-continue-ctrl-c.exp ...
ERROR: Process no longer exists
gdb/ChangeLog:
2018-02-14 Pedro Alves <palves@redhat.com>
* frame-unwind.c (frame_unwind_try_unwinder): Always call
frame_cleanup_after_sniffer on exception.
gdb/testsuite/ChangeLog:
2018-02-14 Pedro Alves <palves@redhat.com>
* gdb.base/bp-cmds-continue-ctrl-c.exp (do_test): Test "bt" after
getting a "Quit".
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.
It is required that unwinder->sniffer should set *this_cache to NULL if
the unwinder is not applicable or exception is thrown, so
78ac5f8316 adds clear_pointer_cleanup to set
*this_cache to NULL in case of exception in order to fix PR 14100.
https://sourceware.org/ml/gdb-patches/2012-08/msg00075.html
This patch removes that clear_pointer_cleanup, and catch all exception in
the caller of unwinder->sniffer. In case of exception, reset *this_case.
gdb:
2017-08-11 Yao Qi <yao.qi@linaro.org>
* dwarf2-frame.c (clear_pointer_cleanup): Remove.
(dwarf2_frame_cache): Remove reset_cache_cleanup.
(dwarf2_frame_cache):
* frame-unwind.c (frame_unwind_try_unwinder): Catch
RETURN_MASK_ALL and set *this_case to NULL.
* frame-unwind.h: Update comments.
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 splits the TRY_CATCH macro into three, so that we go from
this:
~~~
volatile gdb_exception ex;
TRY_CATCH (ex, RETURN_MASK_ERROR)
{
}
if (ex.reason < 0)
{
}
~~~
to this:
~~~
TRY
{
}
CATCH (ex, RETURN_MASK_ERROR)
{
}
END_CATCH
~~~
Thus, we'll be getting rid of the local volatile exception object, and
declaring the caught exception in the catch block.
This allows reimplementing TRY/CATCH in terms of C++ exceptions when
building in C++ mode, while still allowing to build GDB in C mode
(using setjmp/longjmp), as a transition step.
TBC, after this patch, is it _not_ valid to have code between the TRY
and the CATCH blocks, like:
TRY
{
}
// some code here.
CATCH (ex, RETURN_MASK_ERROR)
{
}
END_CATCH
Just like it isn't valid to do that with C++'s native try/catch.
By switching to creating the exception object inside the CATCH block
scope, we can get rid of all the explicitly allocated volatile
exception objects all over the tree, and map the CATCH block more
directly to C++'s catch blocks.
The majority of the TRY_CATCH -> TRY+CATCH+END_CATCH conversion was
done with a script, rerun from scratch at every rebase, no manual
editing involved. After the mechanical conversion, a few places
needed manual intervention, to fix preexisting cases where we were
using the exception object outside of the TRY_CATCH block, and cases
where we were using "else" after a 'if (ex.reason) < 0)' [a CATCH
after this patch]. The result was folded into this patch so that GDB
still builds at each incremental step.
END_CATCH is necessary for two reasons:
First, because we name the exception object in the CATCH block, which
requires creating a scope, which in turn must be closed somewhere.
Declaring the exception variable in the initializer field of a for
block, like:
#define CATCH(EXCEPTION, mask) \
for (struct gdb_exception EXCEPTION; \
exceptions_state_mc_catch (&EXCEPTION, MASK); \
EXCEPTION = exception_none)
would avoid needing END_CATCH, but alas, in C mode, we build with C90,
which doesn't allow mixed declarations and code.
Second, because when TRY/CATCH are wired to real C++ try/catch, as
long as we need to handle cleanup chains, even if there's no CATCH
block that wants to catch the exception, we need for stop at every
frame in the unwind chain and run cleanups, then rethrow. That will
be done in END_CATCH.
After we require C++, we'll still need TRY/CATCH/END_CATCH until
cleanups are completely phased out -- TRY/CATCH in C++ mode will
save/restore the current cleanup chain, like in C mode, and END_CATCH
catches otherwise uncaugh exceptions, runs cleanups and rethrows, so
that C++ cleanups and exceptions can coexist.
IMO, this still makes the TRY/CATCH code look a bit more like a
newcomer would expect, so IMO worth it even if we weren't considering
C++.
gdb/ChangeLog.
2015-03-07 Pedro Alves <palves@redhat.com>
* common/common-exceptions.c (struct catcher) <exception>: No
longer a pointer to volatile exception. Now an exception value.
<mask>: Delete field.
(exceptions_state_mc_init): Remove all parameters. Adjust.
(exceptions_state_mc): No longer pop the catcher here.
(exceptions_state_mc_catch): New function.
(throw_exception): Adjust.
* common/common-exceptions.h (exceptions_state_mc_init): Remove
all parameters.
(exceptions_state_mc_catch): Declare.
(TRY_CATCH): Rename to ...
(TRY): ... this. Remove EXCEPTION and MASK parameters.
(CATCH, END_CATCH): New.
All callers adjusted.
gdb/gdbserver/ChangeLog:
2015-03-07 Pedro Alves <palves@redhat.com>
Adjust all callers of TRY_CATCH to use TRY/CATCH/END_CATCH
instead.
This normalizes some exception catch blocks that check for ex.reason
to look like this:
~~~
volatile gdb_exception ex;
TRY_CATCH (ex, RETURN_MASK_ALL)
{
...
}
if (ex.reason < 0)
{
...
}
~~~
This is a preparation step for running a script that converts all
TRY_CATCH uses to look like this instead:
~~~
TRY
{
...
}
CATCH (ex, RETURN_MASK_ALL)
{
...
}
END_CATCH
~~~
The motivation for that change is being able to reimplent TRY/CATCH in
terms of C++ try/catch.
This commit makes it so that:
- no condition other than ex.reason < 0 is checked in the if
predicate
- there's no "else" block to check whether no exception was caught
- there's no code between the TRY_CATCH (TRY) block and the
'if (ex.reason < 0)' block (CATCH).
- the exception object is no longer referred to outside the if/catch
block. Note the local volatile exception objects that are
currently defined inside functions that use TRY_CATCH will
disappear. In cases it's more convenient to still refer to the
exception outside the catch block, a new non-volatile local is
added and copy to that object is made within the catch block.
The following patches should make this all clearer.
gdb/ChangeLog:
2015-03-07 Pedro Alves <palves@redhat.com>
* amd64-tdep.c (amd64_frame_cache, amd64_sigtramp_frame_cache)
(amd64_epilogue_frame_cache): Normal exception handling code.
* break-catch-throw.c (check_status_exception_catchpoint)
(re_set_exception_catchpoint): Ditto.
* cli/cli-interp.c (safe_execute_command):
* cli/cli-script.c (script_from_file): Ditto.
* compile/compile-c-symbols.c (generate_c_for_for_one_variable):
Ditto.
* compile/compile-object-run.c (compile_object_run): Ditto.
* cp-abi.c (baseclass_offset): Ditto.
* cp-valprint.c (cp_print_value): Ditto.
* exceptions.c (catch_exceptions_with_msg):
* frame-unwind.c (frame_unwind_try_unwinder): Ditto.
* frame.c (get_frame_address_in_block_if_available): Ditto.
* i386-tdep.c (i386_frame_cache, i386_epilogue_frame_cache)
(i386_sigtramp_frame_cache): Ditto.
* infcmd.c (post_create_inferior): Ditto.
* linespec.c (parse_linespec, find_linespec_symbols):
* p-valprint.c (pascal_object_print_value): Ditto.
* parse.c (parse_expression_for_completion): Ditto.
* python/py-finishbreakpoint.c (bpfinishpy_init): Ditto.
* remote.c (remote_get_noisy_reply): Ditto.
* s390-linux-tdep.c (s390_frame_unwind_cache): Ditto.
* solib-svr4.c (solib_svr4_r_map): Ditto.
This fixes PR symtab/14604, PR symtab/14605, and Jan's test at
https://sourceware.org/ml/gdb-patches/2014-07/msg00158.html, in a tree
with bddbbed reverted:
2014-07-22 Pedro Alves <palves@redhat.com>
* value.c (allocate_optimized_out_value): Don't mark value as
non-lazy.
The PRs are about variables described by the DWARF as being split over
multiple registers using DWARF piece information, but some of those
registers being marked as optimised out (not saved) by a later frame.
GDB currently incorrectly mishandles these partially-optimized-out
values.
Even though we can usually tell from the debug info whether a local or
global is optimized out, handling the case of a local living in a
register that was not saved in a frame requires fetching the variable.
GDB also needs to fetch a value to tell whether parts of it are
"<unavailable>". Given this, it's not worth it to try to avoid
fetching lazy optimized-out values based on debug info alone.
So this patch makes GDB track which chunks of a value's contents are
optimized out like it tracks <unavailable> contents. That is, it
makes value->optimized_out be a bit range vector instead of a boolean,
and removes the struct lval_funcs check_validity and check_any_valid
hooks.
Unlike Andrew's series which this is based on (at
https://sourceware.org/ml/gdb-patches/2013-08/msg00300.html, note some
pieces have gone in since), this doesn't merge optimized out and
unavailable contents validity/availability behind a single interface,
nor does it merge the bit range vectors themselves (at least yet).
While it may be desirable to have a single entry point that returns
existence of contents irrespective of what may make them
invalid/unavailable, several places want to treat optimized out /
unavailable / etc. differently, so each spot that potentially could
use it will need to be careful considered on case-by-case basis, and
best done as a separate change.
This fixes Jan's test, because value_available_contents_eq wasn't
considering optimized out value contents. It does now, and because of
that it's been renamed to value_contents_eq.
A new intro comment is added to value.h describing "<optimized out>",
"<not saved>" and "<unavailable>" values.
gdb/
PR symtab/14604
PR symtab/14605
* ada-lang.c (coerce_unspec_val_to_type): Use
value_contents_copy_raw.
* ada-valprint.c (val_print_packed_array_elements): Adjust.
* c-valprint.c (c_val_print): Use value_bits_any_optimized_out.
* cp-valprint.c (cp_print_value_fields): Let the common printing
code handle optimized out values.
(cp_print_value_fields_rtti): Use value_bits_any_optimized_out.
* d-valprint.c (dynamic_array_type): Use
value_bits_any_optimized_out.
* dwarf2loc.c (entry_data_value_funcs): Remove check_validity and
check_any_valid fields.
(check_pieced_value_bits): Delete and inline ...
(check_pieced_synthetic_pointer): ... here.
(check_pieced_value_validity): Delete.
(check_pieced_value_invalid): Delete.
(pieced_value_funcs): Remove check_validity and check_any_valid
fields.
(read_pieced_value): Use mark_value_bits_optimized_out.
(write_pieced_value): Switch to use
mark_value_bytes_optimized_out.
(dwarf2_evaluate_loc_desc_full): Copy the value contents instead
of assuming the whole value is optimized out.
* findvar.c (read_frame_register_value): Remove special handling
of optimized out registers.
(value_from_register): Use mark_value_bytes_optimized_out.
* frame-unwind.c (frame_unwind_got_optimized): Use
mark_value_bytes_optimized_out.
* jv-valprint.c (java_value_print): Adjust.
(java_print_value_fields): Let the common printing code handle
optimized out values.
* mips-tdep.c (mips_print_register): Remove special handling of
optimized out registers.
* opencl-lang.c (lval_func_check_validity): Delete.
(lval_func_check_any_valid): Delete.
(opencl_value_funcs): Remove check_validity and check_any_valid
fields.
* p-valprint.c (pascal_object_print_value_fields): Let the common
printing code handle optimized out values.
* stack.c (read_frame_arg): Remove special handling of optimized
out values. Fetch both VAL and ENTRYVAL before comparing
contents. Adjust to value_available_contents_eq rename.
* valprint.c (valprint_check_validity)
(val_print_scalar_formatted): Use value_bits_any_optimized_out.
(val_print_array_elements): Adjust.
* value.c (struct value) <optimized_out>: Now a VEC(range_s).
(value_bits_any_optimized_out): New function.
(value_entirely_covered_by_range_vector): New function, factored
out from value_entirely_unavailable.
(value_entirely_unavailable): Reimplement.
(value_entirely_optimized_out): New function.
(insert_into_bit_range_vector): New function, factored out from
mark_value_bits_unavailable.
(mark_value_bits_unavailable): Reimplement.
(struct ranges_and_idx): New struct.
(find_first_range_overlap_and_match): New function, factored out
from value_available_contents_bits_eq.
(value_available_contents_bits_eq): Rename to ...
(value_contents_bits_eq): ... this. Check both unavailable
contents and optimized out contents.
(value_available_contents_eq): Rename to ...
(value_contents_eq): ... this.
(allocate_value_lazy): Remove reference to the old optimized_out
boolean.
(allocate_optimized_out_value): Use
mark_value_bytes_optimized_out.
(require_not_optimized_out): Adjust to check whether the
optimized_out vec is empty.
(ranges_copy_adjusted): New function, factored out from
value_contents_copy_raw.
(value_contents_copy_raw): Also copy the optimized out ranges.
Assert the destination ranges aren't optimized out.
(value_contents_copy): Update comment, remove call to
require_not_optimized_out.
(value_contents_equal): Adjust to check whether the optimized_out
vec is empty.
(set_value_optimized_out, value_optimized_out_const): Delete.
(mark_value_bytes_optimized_out, mark_value_bits_optimized_out):
New functions.
(value_entirely_optimized_out, value_bits_valid): Delete.
(value_copy): Take a VEC copy of the 'optimized_out' field.
(value_primitive_field): Remove special handling of optimized out.
(value_fetch_lazy): Assert that lazy values have no unavailable
regions. Use value_bits_any_optimized_out. Remove some special
handling for optimized out values.
* value.h: Add intro comment about <optimized out> and
<unavailable>.
(struct lval_funcs): Remove check_validity and check_any_valid
fields.
(set_value_optimized_out, value_optimized_out_const): Remove.
(mark_value_bytes_optimized_out, mark_value_bits_optimized_out):
New declarations.
(value_bits_any_optimized_out): New declaration.
(value_bits_valid): Delete declaration.
(value_available_contents_eq): Rename to ...
(value_contents_eq): ... this, and extend comments.
gdb/testsuite/
PR symtab/14604
PR symtab/14605
* gdb.dwarf2/dw2-op-out-param.exp: Remove kfail branches and use
gdb_test.
Allow targets to supply their own target-specific frame unwinders; one for
normal frames and one for tailcall frames. If a target-specific unwinder
is supplied, it will be chosen before any other unwinder.
The original patch has been split into this and the next two patches.
gdb/
2013-02-11 Jan Kratochvil <jan.kratochvil@redhat.com>
* frame-unwind.c: Include target.h.
(frame_unwind_try_unwinder): New function with code from ...
(frame_unwind_find_by_frame): ... here. New variable
unwinder_from_target, call also target_get_unwinder)
(target_get_tailcall_unwinder, and frame_unwind_try_unwinder for it.
* target.c (target_get_unwinder, target_get_tailcall_unwinder): New.
* target.h (struct target_ops): New fields to_get_unwinder and
to_get_tailcall_unwinder.
(target_get_unwinder, target_get_tailcall_unwinder): New declarations.
After the previous patch, it should be clear that the
this_frame->unwind->stop_reason check is redundant with the
outer_frame_id check just below. We can now move the frame_id_eq
comparison to the default this_frame->unwind->stop_reason callback.
Tested on x86_64 Fedora 17.
gdb/
2013-11-28 Pedro Alves <palves@redhat.com>
* frame-unwind.c (default_frame_unwind_stop_reason): Return
UNWIND_OUTERMOST if the frame's ID is outer_frame_id.
* frame.c (get_prev_frame_1): Remove outer_frame_id check.
value_of_register_lazy uses the type of REGNUM in FRAME, but given
multi-arch, the arch of FRAME might be different from the previous
frame's arch, and therefore the type of register REGNUM should be
retrieved from the unwound arch. This used to be correct before the
previous change.
Tested on x86_64 Fedora 17.
gdb/
2013-11-27 Pedro Alves <palves@redhat.com>
* frame-unwind.c (frame_unwind_got_optimized): Use the type of the
register in the previous frame's arch.
"set debug frame 1" is printing "<optimized out>" for not saved
registers. That's because the unwinders are returning optimized out
not_lval values instead of optimized out lval_register values. "<not
saved>" is how val_print_optimized_out prints lval_register values.
...
- { frame_unwind_register_value (frame=0,regnum=7(rsp),...) -> <optimized out> }
+ { frame_unwind_register_value (frame=0,regnum=7(rsp),...) -> <not saved> }
...
Tested on x86_64 Fedora 17.
2013-11-27 Pedro Alves <palves@redhat.com>
* frame-unwind.c (frame_unwind_got_optimized): Return
an lval_register value instead of a not_lval value.
Allocate the value as optimized out from the start rather than allocating
a value with contents, and then marking it optimized out.
gdb/
2013-07-04 Pedro Alves <palves@redhat.com>
* findvar.c (value_of_register): Use allocate_optimized_out_value
if the register has been optimized out, instead of
set_value_optimized_out.
* frame-unwind.c (frame_unwind_got_optimized): Use
allocate_optimized_out_value.
Two modifications:
1. The addition of 2013 to the copyright year range for every file;
2. The use of a single year range, instead of potentially multiple
year ranges, as approved by the FSF.
* frame.c (frame_unwind_register): Throw an error if unwinding the
register failed.
* get_prev_frame_1 (get_prev_frame_1): Ask the unwinder if there's
an unwind stop reason.
(frame_stop_reason_string): Handle UNWIND_UNAVAILABLE.
* frame.h (enum unwind_stop_reason) <UNWIND_OUTERMOST,
UNWIND_UNAVAILABLE>: New.
* inline-frame.c (inline_frame_unwind): Install
default_frame_unwind_stop_reason.
* frame-unwind.c: Include "exceptions.h".
(frame_unwind_find_by_frame): Swallow NOT_AVAILABLE_ERROR errors.
(default_frame_unwind_stop_reason): New.
* frame-unwind.h (frame_unwind_stop_reason_ftype): New typedef.
(default_frame_unwind_stop_reason): Declare.
(struct frame_unwind) <stop_reason>: New function pointer.
* dummy-frame.c: Install default_frame_unwind_stop_reason.
* dwarf2-frame.c: Include exceptions.h.
(struct dwarf2_frame_cache) <unavailable_retaddr>: New field.
(dwarf2_frame_cache): Swallow NOT_AVAILABLE_ERROR errors when
computing the CFA. If such an error was thrown, set
unavailable_retaddr.
(dwarf2_frame_unwind_stop_reason): New.
(dwarf2_frame_this_id): Don't build a frame id if the CFA was
unavailable.
(dwarf2_frame_unwind): Install dwarf2_frame_unwind_stop_reason.
(dwarf2_signal_frame_unwind): Ditto.
* amd64-tdep.c: Include "exceptions.h".
(struct amd64_frame_cache): New field "base_p".
(amd64_init_frame_cache): Clear it.
(amd64_frame_cache_1): New, factored out from amd64_frame_cache.
Avoid reading registers with functions that throw if the register
is not necessary to compute the frame base.
(amd64_frame_cache): Reimplement wrapping amd64_frame_cache_1, and
swallowing NOT_AVAILABLE_ERROR.
(amd64_frame_unwind_stop_reason): New.
(amd64_frame_this_id): Don't build a frame id if the frame base
was unavailable.
(amd64_frame_unwind): Install amd64_frame_unwind_stop_reason.
(amd64_sigtramp_frame_cache): Swallow NOT_AVAILABLE_ERROR, and set
base_p if the frame base was computable.
(amd64_sigtramp_frame_unwind_stop_reason): New.
(amd64_sigtramp_frame_this_id): Don't build a frame id if the
frame base was unavailable.
(amd64_sigtramp_frame_unwind): Install
amd64_sigtramp_frame_unwind_stop_reason.
(amd64_epilogue_frame_cache): Swallow NOT_AVAILABLE_ERROR, and set
base_p if the frame base was computable.
(amd64_epilogue_frame_unwind_stop_reason): New.
(amd64_epilogue_frame_this_id): Don't build a frame id if the
frame base was unavailable.
(amd64_epilogue_frame_unwind): Install
amd64_epilogue_frame_unwind_stop_reason.
* i386-tdep.c: Include "exceptions.h".
(struct i386_frame_cache): New field "base_p".
(i386_init_frame_cache): Clear it.
(i386_frame_cache_1): New, factored out from amd64_frame_cache.
Avoid reading registers with functions that throw if the register
is not necessary to compute the frame base.
(i386_frame_cache): Reimplement wrapping amd64_frame_cache_1, and
swallowing NOT_AVAILABLE_ERROR.
(i386_frame_unwind_stop_reason): New.
(i386_frame_this_id): Don't build a frame id if the frame base was
unavailable.
(i386_frame_prev_register): Handle unavailable SP.
(i386_frame_unwind): Install i386_frame_unwind_stop_reason.
(i386_epilogue_frame_cache): Swallow NOT_AVAILABLE_ERROR, and set
base_p if the frame base was computable.
(i386_epilogue_frame_unwind_stop_reason): New.
(i386_epilogue_frame_this_id): Don't build a frame id if the frame
base was unavailable.
(i386_epilogue_frame_unwind): Install
i386_epilogue_frame_unwind_stop_reason.
(i386_sigtramp_frame_cache): Swallow NOT_AVAILABLE_ERROR, and set
base_p if the frame base was computable.
(i386_sigtramp_frame_unwind_stop_reason): New.
(i386_sigtramp_frame_this_id): Don't build a frame id if the frame
base was unavailable.
(i386_sigtramp_frame_unwind): Install
i386_sigtramp_frame_unwind_stop_reason.
* sentinel-frame.c (sentinel_frame_prev_register): Use the value
type's size, not the register's.
(sentinel_frame_unwind): Install default_frame_unwind_stop_reason.
* alpha-mdebug-tdep.c (alpha_mdebug_frame_unwind): Install
default_frame_unwind_stop_reason.
* alpha-tdep.c (alpha_sigtramp_frame_unwind)
(alpha_heuristic_frame_unwind): Ditto.
* amd64obsd-tdep.c (amd64obsd_trapframe_unwind): Ditto.
* arm-tdep.c (arm_prologue_unwind, arm_stub_unwind): Ditto.
* avr-tdep.c (avr_frame_unwind): Ditto.
* cris-tdep.c (cris_sigtramp_frame_unwind, cris_frame_unwind):
Ditto.
* frv-linux-tdep.c (frv_linux_sigtramp_frame_unwind): Ditto.
* frv-tdep.c (frv_frame_unwind): Ditto.
* h8300-tdep.c (h8300_frame_unwind): Ditto.
* hppa-hpux-tdep.c (hppa_hpux_sigtramp_frame_unwind): Ditto.
* hppa-linux-tdep.c (hppa_linux_sigtramp_frame_unwind): Ditto.
* hppa-tdep.c (hppa_frame_unwind, hppa_fallback_frame_unwind)
(hppa_stub_frame_unwind): Ditto.
* i386obsd-tdep.c (i386obsd_trapframe_unwind): Ditto.
* ia64-tdep.c (ia64_frame_unwind, ia64_sigtramp_frame_unwind)
(ia64_libunwind_frame_unwind)
(ia64_libunwind_sigtramp_frame_unwind): Ditto.
* iq2000-tdep.c (iq2000_frame_unwind): Ditto.
* lm32-tdep.c (lm32_frame_unwind): Ditto.
* m32c-tdep.c (m32c_unwind): Ditto.
* m32r-linux-tdep.c (m32r_linux_sigtramp_frame_unwind): Ditto.
* m32r-tdep.c (m32r_frame_unwind): Ditto.
* m68hc11-tdep.c (m68hc11_frame_unwind): Ditto.
* m68k-tdep.c (m68k_frame_unwind): Ditto.
* m68klinux-tdep.c (m68k_linux_sigtramp_frame_unwind): Ditto.
* m88k-tdep.c (m88k_frame_unwind): Ditto.
* mep-tdep.c (mep_frame_unwind): Ditto.
* microblaze-tdep.c (microblaze_frame_unwind): Ditto.
* mips-tdep.c (mips_insn16_frame_unwind, mips_insn32_frame_unwind)
(mips_stub_frame_unwind): Ditto.
* mn10300-tdep.c (mn10300_frame_unwind): Ditto.
* moxie-tdep.c (moxie_frame_unwind): Ditto.
* mt-tdep.c (mt_frame_unwind): Ditto.
* ppc-linux-tdep.c (ppu2spu_unwind): Ditto.
* ppcobsd-tdep.c (ppcobsd_sigtramp_frame_unwind): Ditto.
* rs6000-tdep.c (rs6000_frame_unwind): Ditto.
* s390-tdep.c (s390_frame_unwind, s390_stub_frame_unwind)
(s390_sigtramp_frame_unwind): Ditto.
* score-tdep.c (score_prologue_unwind): Ditto.
* sh-tdep.c (sh_frame_unwind): Ditto.
* sh64-tdep.c (sh64_frame_unwind): Ditto.
* sparc-sol2-tdep.c (sparc32_sol2_sigtramp_frame_unwind): Ditto.
* sparc-tdep.c (sparc32_frame_unwind): Ditto.
* sparc64-sol2-tdep.c (sparc64_sol2_sigtramp_frame_unwind): Ditto.
* sparc64-tdep.c (sparc64_frame_unwind): Ditto.
* sparc64fbsd-tdep.c (sparc64fbsd_sigtramp_frame_unwind): Ditto.
* sparc64nbsd-tdep.c (sparc64nbsd_sigcontext_frame_unwind): Ditto.
* sparc64obsd-tdep.c (sparc64obsd_frame_unwind)
(sparc64obsd_trapframe_unwind): Ditto.
* sparcnbsd-tdep.c (sparc32nbsd_sigcontext_frame_unwind): Ditto.
* sparcobsd-tdep.c (sparc32obsd_sigtramp_frame_unwind): Ditto.
* spu-tdep.c (spu_frame_unwind, spu2ppu_unwind): Ditto.
* v850-tdep.c (v850_frame_unwind): Ditto.
* vax-tdep.c (vax_frame_unwind): Ditto.
* vaxobsd-tdep.c (vaxobsd_sigtramp_frame_unwind): Ditto.
* xstormy16-tdep.c (frame_unwind xstormy16_frame_unwind): Ditto.
* xtensa-tdep.c (xtensa_unwind): Ditto.
Tom Tromey