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.
I forgot to fix some nits pointed out in review before merging the
"frame inlined in outer frame series", this patch fixes them.
gdb/ChangeLog:
* frame-unwind.h (frame_prev_register_ftype): Fix adjective
ordering in comment.
* frame.c (frame_id_eq): Fix indentation.
gdb/testsuite/ChangeLog:
* gdb.dwarf2/dw2-reg-undefined.exp: Remove spurious #.
Change-Id: Iaddde9677fc3f68382558d1a16f5a0b4beb78bac
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 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.
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.
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.
Code cleanup.
* frame-unwind.c (frame_unwind_find_by_frame): Remove the return type
and returned value. New comment from frame-unwind.h.
* frame-unwind.h (frame_unwind_find_by_frame): Remove the return type.
Extend the comment.
* frame.c (get_frame_id, frame_unwind_register_value)
(create_new_frame, get_prev_frame_1, frame_unwinder_is)
(get_frame_type, frame_unwind_arch): Do not use the return value of
frame_unwind_find_by_frame.
* sentinel-frame.c (sentinel_frame_prev_pc): New function.
(sentinel_frame_unwinder): Add the prev_pc method.
* frame.c (frame_pc_unwind): Use the per-frame pc unwinder when
available. Do not handle the sentinel-frame case.
* frame-unwind.h (frame_prev_register_ftype): Define.
(struct frame_unwind): Add prev_pc;
* frame.c (get_prev_frame): Do not call frame_type_from_pc. Set
the frame's type from the unwinder.
(get_frame_type): Map UNKNOWN_FRAME onto NORMAL_FRAME.
(create_new_frame, legacy_get_prev_frame): When the unwinder's
type isn't UNKNOWN_FRAME, initalize "type" from the unwinder.
(get_frame_base_address): Use get_frame_type.
(get_frame_locals_address, get_frame_args_address): Ditto.
(legacy_saved_regs_unwinder): Set the type to UNKNOWN_TYPE.
* frame.h (enum frame_type): Add UNKNOWN_FRAME.
(struct frame_info): Add comment explaining why the frame contains
a "type" field.
* dummy-frame.c (dummy_frame_unwind): Set the type to DUMMY_FRAME.
* d10v-tdep.c (d10v_frame_unwind): Set the type to NORMAL_FRAME.
* sentinel-frame.c (sentinel_frame_unwinder): Set the type to
NORMAL_FRAME.
* frame-unwind.h: Include "frame.h".
(struct frame_unwind): Add "type" field.
* Makefile.in (frame_unwind_h): Add $(frame_h).
