This patch fixes a problem that prevented use of the Dwarf unwinders on SPU,
because dwarf2-frame.c common code did not support the situation where the
stack and/or frame pointer is maintained in a *vector* register. This is
because read_addr_from_reg is hard-coded to assume that such pointers can
be read from registers via a simple get_frame_register / unpack_pointer
operation.
Now, there *is* a routine address_from_register that calls into the
appropriate tdep routines to handle pointer values in "weird" registers
like on SPU, but it turns out I cannot simply change dwarf2-frame.c to
use address_from_register. This is because address_from_register uses
value_from_register to create a (temporary) value, and that routine
at some point calls get_frame_id in order to set up that value's
VALUE_FRAME_ID entry.
However, the dwarf2-frame.c read_addr_from_reg routine will be called
during early unwinding (to unwind the frame's CFA), at which point the
frame's ID is not actually known yet! This would cause an assert.
On the other hand, we may notice that VALUE_FRAME_ID is only needed in the
value returned by value_from_register if that value is later used as an
lvalue. But this is obviously never done to the temporary value used in
address_from_register. So, if we could change address_from_register to
not call value_from_register but instead accept constructing a value
that doesn't have VALUE_FRAME_ID set, things should be fine.
To do that, we can change the value_from_register callback to accept
a FRAME_ID instead of a FRAME; the only existing uses of the FRAME
argument were either to extract its frame ID, or its gdbarch. (To
keep a way of getting at the latter, we also change the callback's
type from "f" to "m".) Together with the required follow-on changes
in the existing value_from_register implementations (including the
default one), this seems to fix the problem.
As another minor interface cleanup, I've removed the explicit TYPE
argument from address_from_register. This routine really always
uses a default pointer type, and in the new implementation it -to
some extent- relies on that fact, in that it will now no longer
handle types that require gdbarch_convert_register_p handling.
gdb:
2014-04-17 Ulrich Weigand <uweigand@de.ibm.com>
* gdbarch.sh (value_from_register): Make class "m" instead of "f".
Replace FRAME argument with FRAME_ID.
* gdbarch.c, gdbarch.h: Regenerate.
* findvar.c (default_value_from_register): Add GDBARCH argument;
replace FRAME by FRAME_ID. No longer call get_frame_id.
(value_from_register): Update call to gdbarch_value_from_register.
* value.h (default_value_from_register): Update prototype.
* s390-linux-tdep.c (s390_value_from_register): Update interface
and call to default_value_from_register.
* spu-tdep.c (spu_value_from_register): Likewise.
* findvar.c (address_from_register): Remove TYPE argument.
Do not call value_from_register; use gdbarch_value_from_register
with null_frame_id instead.
* value.h (address_from_register): Update prototype.
* dwarf2-frame.c (read_addr_from_reg): Use address_from_register.
* dwarf2loc.c (dwarf_expr_read_addr_from_reg): Update for
address_from_register interface change.
Extend the always failing unwinder to provide the PC based on the call
structure detected in the branch trace.
The unwinder supports normal frames and tailcall frames.
Inline frames are not supported.
2014-01-16 Markus Metzger <markus.t.metzger@intel.com>
* record.h (record_btrace_frame_unwind)
(record_btrace_tailcall_frame_unwind): New declarations.
* dwarf2-frame: Include record.h
(dwarf2_frame_cfa): Throw an error for btrace frames.
* record-btrace.c: Include hashtab.h.
(btrace_get_bfun_name): New.
(btrace_call_history): Call btrace_get_bfun_name.
(struct btrace_frame_cache): New.
(bfcache): New.
(bfcache_hash, bfcache_eq, bfcache_new): New.
(btrace_get_frame_function): New.
(record_btrace_frame_unwind_stop_reason): Allow unwinding.
(record_btrace_frame_this_id): Compute own id.
(record_btrace_frame_prev_register): Provide PC, throw_error
for all other registers.
(record_btrace_frame_sniffer): Detect btrace frames.
(record_btrace_tailcall_frame_sniffer): New.
(record_btrace_frame_dealloc_cache): New.
(record_btrace_frame_unwind): Add new functions.
(record_btrace_tailcall_frame_unwind): New.
(_initialize_record_btrace): Allocate cache.
* btrace.c (btrace_clear): Call reinit_frame_cache.
* NEWS: Announce it.
testsuite/
* gdb.btrace/record_goto.exp: Add backtrace test.
* gdb.btrace/tailcall.exp: Add backtrace test.
Swap the unwind stop reason check and the unwinder check to allow
non-dwarf2 frame types to fail with a recoverable error.
gdb/
2013-02-11 Jan Kratochvil <jan.kratochvil@redhat.com>
* dwarf2-frame.c (dwarf2_frame_cfa): Move UNWIND_UNAVAILABLE check
earlier.
Like when stepping, the current stack frame location is expected to be
printed as result of tfind command, if that results in moving to a
different function. In tfind_1 we see:
if (from_tty
&& (has_stack_frames () || traceframe_number >= 0))
{
enum print_what print_what;
/* NOTE: in imitation of the step command, try to determine
whether we have made a transition from one function to
another. If so, we'll print the "stack frame" (ie. the new
function and it's arguments) -- otherwise we'll just show the
new source line. */
if (frame_id_eq (old_frame_id,
get_frame_id (get_current_frame ())))
print_what = SRC_LINE;
else
print_what = SRC_AND_LOC;
print_stack_frame (get_selected_frame (NULL), 1, print_what, 1);
do_displays ();
}
However, when we haven't collected any registers in the tracepoint
(collect $regs), that doesn't actually work:
(gdb) tstart
(gdb) info tracepoints
Num Type Disp Enb Address What
1 tracepoint keep y 0x080483b7 in func0
at ../.././../git/gdb/testsuite/gdb.trace/circ.c:28
collect testload
installed on target
2 tracepoint keep y 0x080483bc in func1
at ../.././../git/gdb/testsuite/gdb.trace/circ.c:32
collect testload
installed on target
(gdb) c
Continuing.
Breakpoint 3, end () at ../.././../git/gdb/testsuite/gdb.trace/circ.c:72
72 }
(gdb) tstop
(gdb) tfind start
Found trace frame 0, tracepoint 1
#0 func0 () at ../.././../git/gdb/testsuite/gdb.trace/circ.c:28
28 }
(gdb) tfind
Found trace frame 1, tracepoint 2
32 }
(gdb)
When we don't have info about the stack available
(UNWIND_UNAVAILABLE), frames end up with outer_frame_id as frame ID.
And in the scenario above, the issue is that both frames before and
after the second tfind (the frames for func0 an func1) have the same
id (outer_frame_id), so the frame_id_eq check returns false, even
though the frames were of different functions. GDB knows that,
because the PC is inferred from the tracepoint's address, even if no
registers were collected.
To fix this, this patch adds support for frame ids with a valid code
address, but <unavailable> stack address, and then makes the unwinders
use that instead of the catch-all outer_frame_id for such frames. The
frame_id_eq check in tfind_1 then automatically does the right thing
as expected.
I tested with --directory=gdb.trace/ , before/after the patch, and
compared the resulting gdb.logs, then adjusted the tests to expect the
extra output that came out. Turns out that was only circ.exp, the
original test that actually brought this issue to light.
Tested on x86_64 Fedora 17, native and gdbserver.
gdb/
2013-12-17 Pedro Alves <palves@redhat.com>
* frame.h (enum frame_id_stack_status): New enum.
(struct frame_id) <stack_addr>: Adjust comment.
<stack_addr_p>: Delete field, replaced with ...
<stack_status>: ... this new field.
(frame_id_build_unavailable_stack): Declare.
* frame.c (frame_addr_hash, fprint_field, outer_frame_id)
(frame_id_build_special): Adjust.
(frame_id_build_unavailable_stack): New function.
(frame_id_build, frame_id_build_wild): Adjust.
(frame_id_p, frame_id_eq, frame_id_inner): Adjust to take into
account frames with unavailable stack.
* amd64-tdep.c (amd64_frame_this_id)
(amd64_sigtramp_frame_this_id, amd64_epilogue_frame_this_id): Use
frame_id_build_unavailable_stack.
* dwarf2-frame.c (dwarf2_frame_this_id): Likewise.
* i386-tdep.c (i386_frame_this_id, i386_epilogue_frame_this_id)
(i386_sigtramp_frame_this_id): Likewise.
gdb/testsuite/
2013-12-17 Pedro Alves <palves@redhat.com>
* gdb.trace/circ.exp: Expect frame info to be printed when
switching between frames with unavailable stack, but different
functions.
This reverts da2b2fdf57 and some
follow-up patches. They were incorrect.
2013-11-26 Tom Tromey <tromey@redhat.com>
* dwarf2-frame.c (dwarf2_frame_cache): Revert patch from
2013-11-22.
2013-11-26 Tom Tromey <tromey@redhat.com>
* gdb.dwarf2/dw2-unspecified-ret-addr.S: Remove.
* gdb.dwarf2/dw2-unspecified-ret-addr.c: Remove.
* gdb.dwarf2/dw2-unspecified-ret-addr.exp: Remove.
Debugging PR 16155 further, I found that the DWARF unwinder found the
function in question, but thought it had no registers saved
(fs->regs.num_regs == 0).
It seems to me that if a frame does not specify the return address
column, or if the return address column is explicitly marked as
DWARF2_FRAME_REG_UNSPECIFIED, then we should set the
"undefined_retaddr" flag and let the DWARF unwinder gracefully stop.
This patch implements that idea.
With this patch the backtrace works properly:
(gdb) bt
#0 0x0000007fb7ed485c in nanosleep () from /lib64/libc.so.6
#1 0x0000007fb7ed4508 in sleep () from /lib64/libc.so.6
#2 0x00000000004008bc in thread_function (arg=0x4) at threadapply.c:73
#3 0x0000007fb7fad950 in start_thread () from /lib64/libpthread.so.0
#4 0x0000007fb7f0956c in clone () from /lib64/libc.so.6
2013-11-22 Tom Tromey <tromey@redhat.com>
PR backtrace/16155:
* dwarf2-frame.c (dwarf2_frame_cache): Set undefined_retaddr if
the return address column is unspecified.
2013-11-22 Tom Tromey <tromey@redhat.com>
* gdb.dwarf2/dw2-bad-cfi.c: New file.
* gdb.dwarf2/dw2-bad-cfi.exp: New file.
* gdb.dwarf2/dw2-bad-cfi.S: New file.
Two rationales, same patch.
TL;DR 1:
dwarf2_frame_cache recursion is evil. dwarf2_frame_cache calls
dwarf2_tailcall_sniffer_first which then recurses into
dwarf2_frame_cache.
TL;DR 2:
An unwinder trying to unwind is evil. dwarf2_frame_sniffer calls
dwarf2_frame_cache which calls dwarf2_tailcall_sniffer_first which
then tries to unwind the PC of the previous frame.
Avoid all that by deferring dwarf2_tailcall_sniffer_first until it's
really necessary.
Rationale 1
===========
A frame sniffer should not try to unwind, because that bypasses all
the validation checks done by get_prev_frame. The UNWIND_SAME_ID
scenario is one such case where GDB is currently broken because (in
part) of this (the next patch adds a test that would fail without
this).
GDB goes into an infinite loop in value_fetch_lazy, here:
while (VALUE_LVAL (new_val) == lval_register && value_lazy (new_val))
{
frame = frame_find_by_id (VALUE_FRAME_ID (new_val));
...
new_val = get_frame_register_value (frame, regnum);
}
(top-gdb) bt
#0 value_fetch_lazy (val=0x11516d0) at ../../src/gdb/value.c:3510
#1 0x0000000000584bd8 in value_optimized_out (value=0x11516d0) at ../../src/gdb/value.c:1096
#2 0x00000000006fe7a1 in frame_register_unwind (frame=0x1492600, regnum=16, optimizedp=0x7fffffffcdec, unavailablep=0x7fffffffcde8, lvalp=0x7fffffffcdd8, addrp=
0x7fffffffcde0, realnump=0x7fffffffcddc, bufferp=0x7fffffffce10 "@\316\377\377\377\177") at ../../src/gdb/frame.c:940
#3 0x00000000006fea3a in frame_unwind_register (frame=0x1492600, regnum=16, buf=0x7fffffffce10 "@\316\377\377\377\177") at ../../src/gdb/frame.c:990
#4 0x0000000000473b9b in i386_unwind_pc (gdbarch=0xf54660, next_frame=0x1492600) at ../../src/gdb/i386-tdep.c:1771
#5 0x0000000000601dfa in gdbarch_unwind_pc (gdbarch=0xf54660, next_frame=0x1492600) at ../../src/gdb/gdbarch.c:2870
#6 0x0000000000693db5 in dwarf2_tailcall_sniffer_first (this_frame=0x1492600, tailcall_cachep=0x14926f0, entry_cfa_sp_offsetp=0x7fffffffcf00)
at ../../src/gdb/dwarf2-frame-tailcall.c:389
#7 0x0000000000690928 in dwarf2_frame_cache (this_frame=0x1492600, this_cache=0x1492618) at ../../src/gdb/dwarf2-frame.c:1245
#8 0x0000000000690f46 in dwarf2_frame_sniffer (self=0x8e4980, this_frame=0x1492600, this_cache=0x1492618) at ../../src/gdb/dwarf2-frame.c:1423
#9 0x000000000070203b in frame_unwind_find_by_frame (this_frame=0x1492600, this_cache=0x1492618) at ../../src/gdb/frame-unwind.c:112
#10 0x00000000006fd681 in get_frame_id (fi=0x1492600) at ../../src/gdb/frame.c:408
#11 0x00000000007006c2 in get_prev_frame_1 (this_frame=0xdc1860) at ../../src/gdb/frame.c:1826
#12 0x0000000000700b7a in get_prev_frame (this_frame=0xdc1860) at ../../src/gdb/frame.c:2056
#13 0x0000000000514588 in frame_info_to_frame_object (frame=0xdc1860) at ../../src/gdb/python/py-frame.c:322
#14 0x000000000051784c in bootstrap_python_frame_filters (frame=0xdc1860, frame_low=0, frame_high=-1) at ../../src/gdb/python/py-framefilter.c:1396
#15 0x0000000000517a6f in apply_frame_filter (frame=0xdc1860, flags=7, args_type=CLI_SCALAR_VALUES, out=0xed7a90, frame_low=0, frame_high=-1)
at ../../src/gdb/python/py-framefilter.c:1492
#16 0x00000000005e77b0 in backtrace_command_1 (count_exp=0x0, show_locals=0, no_filters=0, from_tty=1) at ../../src/gdb/stack.c:1777
#17 0x00000000005e7c0f in backtrace_command (arg=0x0, from_tty=1) at ../../src/gdb/stack.c:1891
#18 0x00000000004e37a7 in do_cfunc (c=0xda4fa0, args=0x0, from_tty=1) at ../../src/gdb/cli/cli-decode.c:107
#19 0x00000000004e683c in cmd_func (cmd=0xda4fa0, args=0x0, from_tty=1) at ../../src/gdb/cli/cli-decode.c:1882
#20 0x00000000006f35ed in execute_command (p=0xcc66c2 "", from_tty=1) at ../../src/gdb/top.c:468
#21 0x00000000005f8853 in command_handler (command=0xcc66c0 "bt") at ../../src/gdb/event-top.c:435
#22 0x00000000005f8e12 in command_line_handler (rl=0xfe05f0 "@") at ../../src/gdb/event-top.c:632
#23 0x000000000074d2c6 in rl_callback_read_char () at ../../src/readline/callback.c:220
#24 0x00000000005f8375 in rl_callback_read_char_wrapper (client_data=0x0) at ../../src/gdb/event-top.c:164
#25 0x00000000005f876a in stdin_event_handler (error=0, client_data=0x0) at ../../src/gdb/event-top.c:375
#26 0x00000000005f72fa in handle_file_event (data=...) at ../../src/gdb/event-loop.c:768
#27 0x00000000005f67a3 in process_event () at ../../src/gdb/event-loop.c:342
#28 0x00000000005f686a in gdb_do_one_event () at ../../src/gdb/event-loop.c:406
#29 0x00000000005f68bb in start_event_loop () at ../../src/gdb/event-loop.c:431
#30 0x00000000005f83a7 in cli_command_loop (data=0x0) at ../../src/gdb/event-top.c:179
#31 0x00000000005eeed3 in current_interp_command_loop () at ../../src/gdb/interps.c:327
#32 0x00000000005ef8ff in captured_command_loop (data=0x0) at ../../src/gdb/main.c:267
#33 0x00000000005ed2f6 in catch_errors (func=0x5ef8e4 <captured_command_loop>, func_args=0x0, errstring=0x8b6554 "", mask=RETURN_MASK_ALL)
at ../../src/gdb/exceptions.c:524
#34 0x00000000005f0d21 in captured_main (data=0x7fffffffd9e0) at ../../src/gdb/main.c:1067
#35 0x00000000005ed2f6 in catch_errors (func=0x5efb9b <captured_main>, func_args=0x7fffffffd9e0, errstring=0x8b6554 "", mask=RETURN_MASK_ALL)
at ../../src/gdb/exceptions.c:524
#36 0x00000000005f0d57 in gdb_main (args=0x7fffffffd9e0) at ../../src/gdb/main.c:1076
#37 0x000000000045bb6a in main (argc=4, argv=0x7fffffffdae8) at ../../src/gdb/gdb.c:34
(top-gdb)
GDB is trying to unwind the PC register of the previous frame (frame
#5 above), starting from the frame being sniffed (the THIS frame).
But the THIS frame's unwinder says the PC of the previous frame is
actually the same as the previous's frame's next frame (which is the
same frame we started with, the THIS frame), therefore it returns an
lval_register lazy value with frame set to THIS frame. And so the
value_fetch_lazy loop never ends.
Rationale 2
===========
As an experiment, I tried making dwarf2-frame.c:read_addr_from_reg use
address_from_register. That caused a bunch of regressions, but it
actually took me a long while to figure out what was going on. Turns
out dwarf2-frame.c:read_addr_from_reg is called while computing the
frame's CFA, from within dwarf2_frame_cache. address_from_register
wants to create a register with frame_id set to the frame being
constructed. To create the frame id, we again call dwarf2_frame_cache,
which given:
static struct dwarf2_frame_cache *
dwarf2_frame_cache (struct frame_info *this_frame, void **this_cache)
{
...
if (*this_cache)
return *this_cache;
returns an incomplete object to the caller:
static void
dwarf2_frame_this_id (struct frame_info *this_frame, void **this_cache,
struct frame_id *this_id)
{
struct dwarf2_frame_cache *cache =
dwarf2_frame_cache (this_frame, this_cache);
...
(*this_id) = frame_id_build (cache->cfa, get_frame_func (this_frame));
}
As cache->cfa is still 0 (we were trying to compute it!), and
get_frame_id recalls this id from here on, we end up with a broken
frame id in recorded for this frame. Later, when inspecting locals,
the dwarf machinery needs to know the selected frame's base, which
calls get_frame_base:
CORE_ADDR
get_frame_base (struct frame_info *fi)
{
return get_frame_id (fi).stack_addr;
}
which as seen above then returns 0 ...
So I gave up using address_from_register.
But, the pain of investigating this made me want to have GDB itself
assert that recursion never happens here. So I wrote a patch to do
that. But, it triggers on current mainline, because
dwarf2_tailcall_sniffer_first, called from dwarf2_frame_cache, unwinds
the this_frame.
A sniffer shouldn't be trying to unwind, exactly because of this sort
of tricky issue. The patch defers calling
dwarf2_tailcall_sniffer_first until it's really necessary, in
dwarf2_frame_prev_register (thus actually outside the sniffer path).
As this makes the call to dwarf2_frame_sniffer in dwarf2_frame_cache
unnecessary again, the patch removes that too.
Tested on x86_64 Fedora 17.
gdb/
2013-11-22 Pedro Alves <palves@redhat.com>
PR 16155
* dwarf2-frame.c (struct dwarf2_frame_cache)
<checked_tailcall_bottom, entry_cfa_sp_offset,
entry_cfa_sp_offset_p>: New fields.
(dwarf2_frame_cache): Adjust to use the new cache fields instead
of locals. Don't call dwarf2_tailcall_sniffer_first here.
(dwarf2_frame_prev_register): Call it here, but only once.
Two rationales, same patch.
TL;DR 1:
dwarf2_frame_cache recursion is evil. dwarf2_frame_cache calls
dwarf2_tailcall_sniffer_first which then recurses into
dwarf2_frame_cache.
TL;DR 2:
An unwinder trying to unwind is evil. dwarf2_frame_sniffer calls
dwarf2_frame_cache which calls dwarf2_tailcall_sniffer_first which
then tries to unwind the PC of the previous frame.
Avoid all that by deferring dwarf2_tailcall_sniffer_first until it's
really necessary.
Rationale 1
===========
A frame sniffer should not try to unwind, because that bypasses all
the validation checks done by get_prev_frame. The UNWIND_SAME_ID
scenario is one such case where GDB is currently broken because (in
part) of this (the next patch adds a test that would fail without
this).
GDB goes into an infinite loop in value_fetch_lazy, here:
while (VALUE_LVAL (new_val) == lval_register && value_lazy (new_val))
{
frame = frame_find_by_id (VALUE_FRAME_ID (new_val));
...
new_val = get_frame_register_value (frame, regnum);
}
(top-gdb) bt
#0 value_fetch_lazy (val=0x11516d0) at ../../src/gdb/value.c:3510
#1 0x0000000000584bd8 in value_optimized_out (value=0x11516d0) at ../../src/gdb/value.c:1096
#2 0x00000000006fe7a1 in frame_register_unwind (frame=0x1492600, regnum=16, optimizedp=0x7fffffffcdec, unavailablep=0x7fffffffcde8, lvalp=0x7fffffffcdd8, addrp=
0x7fffffffcde0, realnump=0x7fffffffcddc, bufferp=0x7fffffffce10 "@\316\377\377\377\177") at ../../src/gdb/frame.c:940
#3 0x00000000006fea3a in frame_unwind_register (frame=0x1492600, regnum=16, buf=0x7fffffffce10 "@\316\377\377\377\177") at ../../src/gdb/frame.c:990
#4 0x0000000000473b9b in i386_unwind_pc (gdbarch=0xf54660, next_frame=0x1492600) at ../../src/gdb/i386-tdep.c:1771
#5 0x0000000000601dfa in gdbarch_unwind_pc (gdbarch=0xf54660, next_frame=0x1492600) at ../../src/gdb/gdbarch.c:2870
#6 0x0000000000693db5 in dwarf2_tailcall_sniffer_first (this_frame=0x1492600, tailcall_cachep=0x14926f0, entry_cfa_sp_offsetp=0x7fffffffcf00)
at ../../src/gdb/dwarf2-frame-tailcall.c:389
#7 0x0000000000690928 in dwarf2_frame_cache (this_frame=0x1492600, this_cache=0x1492618) at ../../src/gdb/dwarf2-frame.c:1245
#8 0x0000000000690f46 in dwarf2_frame_sniffer (self=0x8e4980, this_frame=0x1492600, this_cache=0x1492618) at ../../src/gdb/dwarf2-frame.c:1423
#9 0x000000000070203b in frame_unwind_find_by_frame (this_frame=0x1492600, this_cache=0x1492618) at ../../src/gdb/frame-unwind.c:112
#10 0x00000000006fd681 in get_frame_id (fi=0x1492600) at ../../src/gdb/frame.c:408
#11 0x00000000007006c2 in get_prev_frame_1 (this_frame=0xdc1860) at ../../src/gdb/frame.c:1826
#12 0x0000000000700b7a in get_prev_frame (this_frame=0xdc1860) at ../../src/gdb/frame.c:2056
#13 0x0000000000514588 in frame_info_to_frame_object (frame=0xdc1860) at ../../src/gdb/python/py-frame.c:322
#14 0x000000000051784c in bootstrap_python_frame_filters (frame=0xdc1860, frame_low=0, frame_high=-1) at ../../src/gdb/python/py-framefilter.c:1396
#15 0x0000000000517a6f in apply_frame_filter (frame=0xdc1860, flags=7, args_type=CLI_SCALAR_VALUES, out=0xed7a90, frame_low=0, frame_high=-1)
at ../../src/gdb/python/py-framefilter.c:1492
#16 0x00000000005e77b0 in backtrace_command_1 (count_exp=0x0, show_locals=0, no_filters=0, from_tty=1) at ../../src/gdb/stack.c:1777
#17 0x00000000005e7c0f in backtrace_command (arg=0x0, from_tty=1) at ../../src/gdb/stack.c:1891
#18 0x00000000004e37a7 in do_cfunc (c=0xda4fa0, args=0x0, from_tty=1) at ../../src/gdb/cli/cli-decode.c:107
#19 0x00000000004e683c in cmd_func (cmd=0xda4fa0, args=0x0, from_tty=1) at ../../src/gdb/cli/cli-decode.c:1882
#20 0x00000000006f35ed in execute_command (p=0xcc66c2 "", from_tty=1) at ../../src/gdb/top.c:468
#21 0x00000000005f8853 in command_handler (command=0xcc66c0 "bt") at ../../src/gdb/event-top.c:435
#22 0x00000000005f8e12 in command_line_handler (rl=0xfe05f0 "@") at ../../src/gdb/event-top.c:632
#23 0x000000000074d2c6 in rl_callback_read_char () at ../../src/readline/callback.c:220
#24 0x00000000005f8375 in rl_callback_read_char_wrapper (client_data=0x0) at ../../src/gdb/event-top.c:164
#25 0x00000000005f876a in stdin_event_handler (error=0, client_data=0x0) at ../../src/gdb/event-top.c:375
#26 0x00000000005f72fa in handle_file_event (data=...) at ../../src/gdb/event-loop.c:768
#27 0x00000000005f67a3 in process_event () at ../../src/gdb/event-loop.c:342
#28 0x00000000005f686a in gdb_do_one_event () at ../../src/gdb/event-loop.c:406
#29 0x00000000005f68bb in start_event_loop () at ../../src/gdb/event-loop.c:431
#30 0x00000000005f83a7 in cli_command_loop (data=0x0) at ../../src/gdb/event-top.c:179
#31 0x00000000005eeed3 in current_interp_command_loop () at ../../src/gdb/interps.c:327
#32 0x00000000005ef8ff in captured_command_loop (data=0x0) at ../../src/gdb/main.c:267
#33 0x00000000005ed2f6 in catch_errors (func=0x5ef8e4 <captured_command_loop>, func_args=0x0, errstring=0x8b6554 "", mask=RETURN_MASK_ALL)
at ../../src/gdb/exceptions.c:524
#34 0x00000000005f0d21 in captured_main (data=0x7fffffffd9e0) at ../../src/gdb/main.c:1067
#35 0x00000000005ed2f6 in catch_errors (func=0x5efb9b <captured_main>, func_args=0x7fffffffd9e0, errstring=0x8b6554 "", mask=RETURN_MASK_ALL)
at ../../src/gdb/exceptions.c:524
#36 0x00000000005f0d57 in gdb_main (args=0x7fffffffd9e0) at ../../src/gdb/main.c:1076
#37 0x000000000045bb6a in main (argc=4, argv=0x7fffffffdae8) at ../../src/gdb/gdb.c:34
(top-gdb)
GDB is trying to unwind the PC register of the previous frame (frame
#5 above), starting from the frame being sniffed (the THIS frame).
But the THIS frame's unwinder says the PC of the previous frame is
actually the same as the previous's frame's next frame (which is the
same frame we started with, the THIS frame), therefore it returns an
lval_register lazy value with frame set to THIS frame. And so the
value_fetch_lazy loop never ends.
Rationale 2
===========
As an experiment, I tried making dwarf2-frame.c:read_addr_from_reg use
address_from_register. That caused a bunch of regressions, but it
actually took me a long while to figure out what was going on. Turns
out dwarf2-frame.c:read_addr_from_reg is called while computing the
frame's CFA, from within dwarf2_frame_cache. address_from_register
wants to create a register with frame_id set to the frame being
constructed. To create the frame id, we again call dwarf2_frame_cache,
which given:
static struct dwarf2_frame_cache *
dwarf2_frame_cache (struct frame_info *this_frame, void **this_cache)
{
...
if (*this_cache)
return *this_cache;
returns an incomplete object to the caller:
static void
dwarf2_frame_this_id (struct frame_info *this_frame, void **this_cache,
struct frame_id *this_id)
{
struct dwarf2_frame_cache *cache =
dwarf2_frame_cache (this_frame, this_cache);
...
(*this_id) = frame_id_build (cache->cfa, get_frame_func (this_frame));
}
As cache->cfa is still 0 (we were trying to compute it!), and
get_frame_id recalls this id from here on, we end up with a broken
frame id in recorded for this frame. Later, when inspecting locals,
the dwarf machinery needs to know the selected frame's base, which
calls get_frame_base:
CORE_ADDR
get_frame_base (struct frame_info *fi)
{
return get_frame_id (fi).stack_addr;
}
which as seen above then returns 0 ...
So I gave up using address_from_register.
But, the pain of investigating this made me want to have GDB itself
assert that recursion never happens here. So I wrote a patch to do
that. But, it triggers on current mainline, because
dwarf2_tailcall_sniffer_first, called from dwarf2_frame_cache, unwinds
the this_frame.
A sniffer shouldn't be trying to unwind, exactly because of this sort
of tricky issue. The patch defers calling
dwarf2_tailcall_sniffer_first until it's really necessary, in
dwarf2_frame_prev_register (thus actually outside the sniffer path).
As this makes the call to dwarf2_frame_sniffer in dwarf2_frame_cache
unnecessary again, the patch removes that too.
Tested on x86_64 Fedora 17.
gdb/
2013-11-22 Pedro Alves <palves@redhat.com>
PR 16155
* dwarf2-frame.c (struct dwarf2_frame_cache)
<checked_tailcall_bottom, entry_cfa_sp_offset,
entry_cfa_sp_offset_p>: New fields.
(dwarf2_frame_cache): Adjust to use the new cache fields instead
of locals. Don't call dwarf2_tailcall_sniffer_first here.
(dwarf2_frame_prev_register): Call it here, but only once.
This removes gdb_string.h. This patch is purely mechanical. I
created it by running the two commands:
git rm common/gdb_string.h
perl -pi -e's/"gdb_string.h"/<string.h>/;' *.[chyl] */*.[chyl]
2013-11-18 Tom Tromey <tromey@redhat.com>
* common/gdb_string.h: Remove.
* aarch64-tdep.c: Use string.h, not gdb_string.h.
* ada-exp.y: Use string.h, not gdb_string.h.
* ada-lang.c: Use string.h, not gdb_string.h.
* ada-lex.l: Use string.h, not gdb_string.h.
* ada-typeprint.c: Use string.h, not gdb_string.h.
* ada-valprint.c: Use string.h, not gdb_string.h.
* aix-thread.c: Use string.h, not gdb_string.h.
* alpha-linux-tdep.c: Use string.h, not gdb_string.h.
* alpha-mdebug-tdep.c: Use string.h, not gdb_string.h.
* alpha-nat.c: Use string.h, not gdb_string.h.
* alpha-osf1-tdep.c: Use string.h, not gdb_string.h.
* alpha-tdep.c: Use string.h, not gdb_string.h.
* alphanbsd-tdep.c: Use string.h, not gdb_string.h.
* amd64-dicos-tdep.c: Use string.h, not gdb_string.h.
* amd64-linux-nat.c: Use string.h, not gdb_string.h.
* amd64-linux-tdep.c: Use string.h, not gdb_string.h.
* amd64-nat.c: Use string.h, not gdb_string.h.
* amd64-sol2-tdep.c: Use string.h, not gdb_string.h.
* amd64fbsd-tdep.c: Use string.h, not gdb_string.h.
* amd64obsd-tdep.c: Use string.h, not gdb_string.h.
* arch-utils.c: Use string.h, not gdb_string.h.
* arm-linux-nat.c: Use string.h, not gdb_string.h.
* arm-linux-tdep.c: Use string.h, not gdb_string.h.
* arm-tdep.c: Use string.h, not gdb_string.h.
* arm-wince-tdep.c: Use string.h, not gdb_string.h.
* armbsd-tdep.c: Use string.h, not gdb_string.h.
* armnbsd-nat.c: Use string.h, not gdb_string.h.
* armnbsd-tdep.c: Use string.h, not gdb_string.h.
* armobsd-tdep.c: Use string.h, not gdb_string.h.
* avr-tdep.c: Use string.h, not gdb_string.h.
* ax-gdb.c: Use string.h, not gdb_string.h.
* ax-general.c: Use string.h, not gdb_string.h.
* bcache.c: Use string.h, not gdb_string.h.
* bfin-tdep.c: Use string.h, not gdb_string.h.
* breakpoint.c: Use string.h, not gdb_string.h.
* build-id.c: Use string.h, not gdb_string.h.
* buildsym.c: Use string.h, not gdb_string.h.
* c-exp.y: Use string.h, not gdb_string.h.
* c-lang.c: Use string.h, not gdb_string.h.
* c-typeprint.c: Use string.h, not gdb_string.h.
* c-valprint.c: Use string.h, not gdb_string.h.
* charset.c: Use string.h, not gdb_string.h.
* cli-out.c: Use string.h, not gdb_string.h.
* cli/cli-cmds.c: Use string.h, not gdb_string.h.
* cli/cli-decode.c: Use string.h, not gdb_string.h.
* cli/cli-dump.c: Use string.h, not gdb_string.h.
* cli/cli-interp.c: Use string.h, not gdb_string.h.
* cli/cli-logging.c: Use string.h, not gdb_string.h.
* cli/cli-script.c: Use string.h, not gdb_string.h.
* cli/cli-setshow.c: Use string.h, not gdb_string.h.
* cli/cli-utils.c: Use string.h, not gdb_string.h.
* coffread.c: Use string.h, not gdb_string.h.
* common/common-utils.c: Use string.h, not gdb_string.h.
* common/filestuff.c: Use string.h, not gdb_string.h.
* common/linux-procfs.c: Use string.h, not gdb_string.h.
* common/linux-ptrace.c: Use string.h, not gdb_string.h.
* common/signals.c: Use string.h, not gdb_string.h.
* common/vec.h: Use string.h, not gdb_string.h.
* core-regset.c: Use string.h, not gdb_string.h.
* corefile.c: Use string.h, not gdb_string.h.
* corelow.c: Use string.h, not gdb_string.h.
* cp-abi.c: Use string.h, not gdb_string.h.
* cp-support.c: Use string.h, not gdb_string.h.
* cp-valprint.c: Use string.h, not gdb_string.h.
* cris-tdep.c: Use string.h, not gdb_string.h.
* d-lang.c: Use string.h, not gdb_string.h.
* dbxread.c: Use string.h, not gdb_string.h.
* dcache.c: Use string.h, not gdb_string.h.
* demangle.c: Use string.h, not gdb_string.h.
* dicos-tdep.c: Use string.h, not gdb_string.h.
* disasm.c: Use string.h, not gdb_string.h.
* doublest.c: Use string.h, not gdb_string.h.
* dsrec.c: Use string.h, not gdb_string.h.
* dummy-frame.c: Use string.h, not gdb_string.h.
* dwarf2-frame.c: Use string.h, not gdb_string.h.
* dwarf2loc.c: Use string.h, not gdb_string.h.
* dwarf2read.c: Use string.h, not gdb_string.h.
* elfread.c: Use string.h, not gdb_string.h.
* environ.c: Use string.h, not gdb_string.h.
* eval.c: Use string.h, not gdb_string.h.
* event-loop.c: Use string.h, not gdb_string.h.
* exceptions.c: Use string.h, not gdb_string.h.
* exec.c: Use string.h, not gdb_string.h.
* expprint.c: Use string.h, not gdb_string.h.
* f-exp.y: Use string.h, not gdb_string.h.
* f-lang.c: Use string.h, not gdb_string.h.
* f-typeprint.c: Use string.h, not gdb_string.h.
* f-valprint.c: Use string.h, not gdb_string.h.
* fbsd-nat.c: Use string.h, not gdb_string.h.
* findcmd.c: Use string.h, not gdb_string.h.
* findvar.c: Use string.h, not gdb_string.h.
* fork-child.c: Use string.h, not gdb_string.h.
* frame.c: Use string.h, not gdb_string.h.
* frv-linux-tdep.c: Use string.h, not gdb_string.h.
* frv-tdep.c: Use string.h, not gdb_string.h.
* gdb.c: Use string.h, not gdb_string.h.
* gdb_bfd.c: Use string.h, not gdb_string.h.
* gdbarch.c: Use string.h, not gdb_string.h.
* gdbtypes.c: Use string.h, not gdb_string.h.
* gnu-nat.c: Use string.h, not gdb_string.h.
* gnu-v2-abi.c: Use string.h, not gdb_string.h.
* gnu-v3-abi.c: Use string.h, not gdb_string.h.
* go-exp.y: Use string.h, not gdb_string.h.
* go-lang.c: Use string.h, not gdb_string.h.
* go32-nat.c: Use string.h, not gdb_string.h.
* hppa-hpux-tdep.c: Use string.h, not gdb_string.h.
* hppa-linux-nat.c: Use string.h, not gdb_string.h.
* hppanbsd-tdep.c: Use string.h, not gdb_string.h.
* hppaobsd-tdep.c: Use string.h, not gdb_string.h.
* i386-cygwin-tdep.c: Use string.h, not gdb_string.h.
* i386-dicos-tdep.c: Use string.h, not gdb_string.h.
* i386-linux-nat.c: Use string.h, not gdb_string.h.
* i386-linux-tdep.c: Use string.h, not gdb_string.h.
* i386-nto-tdep.c: Use string.h, not gdb_string.h.
* i386-sol2-tdep.c: Use string.h, not gdb_string.h.
* i386-tdep.c: Use string.h, not gdb_string.h.
* i386bsd-tdep.c: Use string.h, not gdb_string.h.
* i386gnu-nat.c: Use string.h, not gdb_string.h.
* i386nbsd-tdep.c: Use string.h, not gdb_string.h.
* i386obsd-tdep.c: Use string.h, not gdb_string.h.
* i387-tdep.c: Use string.h, not gdb_string.h.
* ia64-libunwind-tdep.c: Use string.h, not gdb_string.h.
* ia64-linux-nat.c: Use string.h, not gdb_string.h.
* inf-child.c: Use string.h, not gdb_string.h.
* inf-ptrace.c: Use string.h, not gdb_string.h.
* inf-ttrace.c: Use string.h, not gdb_string.h.
* infcall.c: Use string.h, not gdb_string.h.
* infcmd.c: Use string.h, not gdb_string.h.
* inflow.c: Use string.h, not gdb_string.h.
* infrun.c: Use string.h, not gdb_string.h.
* interps.c: Use string.h, not gdb_string.h.
* iq2000-tdep.c: Use string.h, not gdb_string.h.
* irix5-nat.c: Use string.h, not gdb_string.h.
* jv-exp.y: Use string.h, not gdb_string.h.
* jv-lang.c: Use string.h, not gdb_string.h.
* jv-typeprint.c: Use string.h, not gdb_string.h.
* jv-valprint.c: Use string.h, not gdb_string.h.
* language.c: Use string.h, not gdb_string.h.
* linux-fork.c: Use string.h, not gdb_string.h.
* linux-nat.c: Use string.h, not gdb_string.h.
* lm32-tdep.c: Use string.h, not gdb_string.h.
* m2-exp.y: Use string.h, not gdb_string.h.
* m2-typeprint.c: Use string.h, not gdb_string.h.
* m32c-tdep.c: Use string.h, not gdb_string.h.
* m32r-linux-nat.c: Use string.h, not gdb_string.h.
* m32r-linux-tdep.c: Use string.h, not gdb_string.h.
* m32r-rom.c: Use string.h, not gdb_string.h.
* m32r-tdep.c: Use string.h, not gdb_string.h.
* m68hc11-tdep.c: Use string.h, not gdb_string.h.
* m68k-tdep.c: Use string.h, not gdb_string.h.
* m68kbsd-tdep.c: Use string.h, not gdb_string.h.
* m68klinux-nat.c: Use string.h, not gdb_string.h.
* m68klinux-tdep.c: Use string.h, not gdb_string.h.
* m88k-tdep.c: Use string.h, not gdb_string.h.
* macrocmd.c: Use string.h, not gdb_string.h.
* main.c: Use string.h, not gdb_string.h.
* mdebugread.c: Use string.h, not gdb_string.h.
* mem-break.c: Use string.h, not gdb_string.h.
* memattr.c: Use string.h, not gdb_string.h.
* memory-map.c: Use string.h, not gdb_string.h.
* mep-tdep.c: Use string.h, not gdb_string.h.
* mi/mi-cmd-break.c: Use string.h, not gdb_string.h.
* mi/mi-cmd-disas.c: Use string.h, not gdb_string.h.
* mi/mi-cmd-env.c: Use string.h, not gdb_string.h.
* mi/mi-cmd-stack.c: Use string.h, not gdb_string.h.
* mi/mi-cmd-var.c: Use string.h, not gdb_string.h.
* mi/mi-cmds.c: Use string.h, not gdb_string.h.
* mi/mi-console.c: Use string.h, not gdb_string.h.
* mi/mi-getopt.c: Use string.h, not gdb_string.h.
* mi/mi-interp.c: Use string.h, not gdb_string.h.
* mi/mi-main.c: Use string.h, not gdb_string.h.
* mi/mi-parse.c: Use string.h, not gdb_string.h.
* microblaze-rom.c: Use string.h, not gdb_string.h.
* microblaze-tdep.c: Use string.h, not gdb_string.h.
* mingw-hdep.c: Use string.h, not gdb_string.h.
* minidebug.c: Use string.h, not gdb_string.h.
* minsyms.c: Use string.h, not gdb_string.h.
* mips-irix-tdep.c: Use string.h, not gdb_string.h.
* mips-linux-tdep.c: Use string.h, not gdb_string.h.
* mips-tdep.c: Use string.h, not gdb_string.h.
* mips64obsd-tdep.c: Use string.h, not gdb_string.h.
* mipsnbsd-tdep.c: Use string.h, not gdb_string.h.
* mipsread.c: Use string.h, not gdb_string.h.
* mn10300-linux-tdep.c: Use string.h, not gdb_string.h.
* mn10300-tdep.c: Use string.h, not gdb_string.h.
* monitor.c: Use string.h, not gdb_string.h.
* moxie-tdep.c: Use string.h, not gdb_string.h.
* mt-tdep.c: Use string.h, not gdb_string.h.
* nbsd-tdep.c: Use string.h, not gdb_string.h.
* nios2-linux-tdep.c: Use string.h, not gdb_string.h.
* nto-procfs.c: Use string.h, not gdb_string.h.
* nto-tdep.c: Use string.h, not gdb_string.h.
* objc-lang.c: Use string.h, not gdb_string.h.
* objfiles.c: Use string.h, not gdb_string.h.
* opencl-lang.c: Use string.h, not gdb_string.h.
* osabi.c: Use string.h, not gdb_string.h.
* osdata.c: Use string.h, not gdb_string.h.
* p-exp.y: Use string.h, not gdb_string.h.
* p-lang.c: Use string.h, not gdb_string.h.
* p-typeprint.c: Use string.h, not gdb_string.h.
* parse.c: Use string.h, not gdb_string.h.
* posix-hdep.c: Use string.h, not gdb_string.h.
* ppc-linux-nat.c: Use string.h, not gdb_string.h.
* ppc-sysv-tdep.c: Use string.h, not gdb_string.h.
* ppcfbsd-tdep.c: Use string.h, not gdb_string.h.
* ppcnbsd-tdep.c: Use string.h, not gdb_string.h.
* ppcobsd-tdep.c: Use string.h, not gdb_string.h.
* printcmd.c: Use string.h, not gdb_string.h.
* procfs.c: Use string.h, not gdb_string.h.
* prologue-value.c: Use string.h, not gdb_string.h.
* python/py-auto-load.c: Use string.h, not gdb_string.h.
* python/py-gdb-readline.c: Use string.h, not gdb_string.h.
* ravenscar-thread.c: Use string.h, not gdb_string.h.
* regcache.c: Use string.h, not gdb_string.h.
* registry.c: Use string.h, not gdb_string.h.
* remote-fileio.c: Use string.h, not gdb_string.h.
* remote-m32r-sdi.c: Use string.h, not gdb_string.h.
* remote-mips.c: Use string.h, not gdb_string.h.
* remote-sim.c: Use string.h, not gdb_string.h.
* remote.c: Use string.h, not gdb_string.h.
* reverse.c: Use string.h, not gdb_string.h.
* rs6000-aix-tdep.c: Use string.h, not gdb_string.h.
* ser-base.c: Use string.h, not gdb_string.h.
* ser-go32.c: Use string.h, not gdb_string.h.
* ser-mingw.c: Use string.h, not gdb_string.h.
* ser-pipe.c: Use string.h, not gdb_string.h.
* ser-tcp.c: Use string.h, not gdb_string.h.
* ser-unix.c: Use string.h, not gdb_string.h.
* serial.c: Use string.h, not gdb_string.h.
* sh-tdep.c: Use string.h, not gdb_string.h.
* sh64-tdep.c: Use string.h, not gdb_string.h.
* shnbsd-tdep.c: Use string.h, not gdb_string.h.
* skip.c: Use string.h, not gdb_string.h.
* sol-thread.c: Use string.h, not gdb_string.h.
* solib-dsbt.c: Use string.h, not gdb_string.h.
* solib-frv.c: Use string.h, not gdb_string.h.
* solib-osf.c: Use string.h, not gdb_string.h.
* solib-spu.c: Use string.h, not gdb_string.h.
* solib-target.c: Use string.h, not gdb_string.h.
* solib.c: Use string.h, not gdb_string.h.
* somread.c: Use string.h, not gdb_string.h.
* source.c: Use string.h, not gdb_string.h.
* sparc-nat.c: Use string.h, not gdb_string.h.
* sparc-sol2-tdep.c: Use string.h, not gdb_string.h.
* sparc-tdep.c: Use string.h, not gdb_string.h.
* sparc64-tdep.c: Use string.h, not gdb_string.h.
* sparc64fbsd-tdep.c: Use string.h, not gdb_string.h.
* sparc64nbsd-tdep.c: Use string.h, not gdb_string.h.
* sparcnbsd-tdep.c: Use string.h, not gdb_string.h.
* spu-linux-nat.c: Use string.h, not gdb_string.h.
* spu-multiarch.c: Use string.h, not gdb_string.h.
* spu-tdep.c: Use string.h, not gdb_string.h.
* stabsread.c: Use string.h, not gdb_string.h.
* stack.c: Use string.h, not gdb_string.h.
* std-regs.c: Use string.h, not gdb_string.h.
* symfile.c: Use string.h, not gdb_string.h.
* symmisc.c: Use string.h, not gdb_string.h.
* symtab.c: Use string.h, not gdb_string.h.
* target.c: Use string.h, not gdb_string.h.
* thread.c: Use string.h, not gdb_string.h.
* tilegx-linux-nat.c: Use string.h, not gdb_string.h.
* tilegx-tdep.c: Use string.h, not gdb_string.h.
* top.c: Use string.h, not gdb_string.h.
* tracepoint.c: Use string.h, not gdb_string.h.
* tui/tui-command.c: Use string.h, not gdb_string.h.
* tui/tui-data.c: Use string.h, not gdb_string.h.
* tui/tui-disasm.c: Use string.h, not gdb_string.h.
* tui/tui-file.c: Use string.h, not gdb_string.h.
* tui/tui-layout.c: Use string.h, not gdb_string.h.
* tui/tui-out.c: Use string.h, not gdb_string.h.
* tui/tui-regs.c: Use string.h, not gdb_string.h.
* tui/tui-source.c: Use string.h, not gdb_string.h.
* tui/tui-stack.c: Use string.h, not gdb_string.h.
* tui/tui-win.c: Use string.h, not gdb_string.h.
* tui/tui-windata.c: Use string.h, not gdb_string.h.
* tui/tui-winsource.c: Use string.h, not gdb_string.h.
* typeprint.c: Use string.h, not gdb_string.h.
* ui-file.c: Use string.h, not gdb_string.h.
* ui-out.c: Use string.h, not gdb_string.h.
* user-regs.c: Use string.h, not gdb_string.h.
* utils.c: Use string.h, not gdb_string.h.
* v850-tdep.c: Use string.h, not gdb_string.h.
* valarith.c: Use string.h, not gdb_string.h.
* valops.c: Use string.h, not gdb_string.h.
* valprint.c: Use string.h, not gdb_string.h.
* value.c: Use string.h, not gdb_string.h.
* varobj.c: Use string.h, not gdb_string.h.
* vax-tdep.c: Use string.h, not gdb_string.h.
* vaxnbsd-tdep.c: Use string.h, not gdb_string.h.
* vaxobsd-tdep.c: Use string.h, not gdb_string.h.
* windows-nat.c: Use string.h, not gdb_string.h.
* xcoffread.c: Use string.h, not gdb_string.h.
* xml-support.c: Use string.h, not gdb_string.h.
* xstormy16-tdep.c: Use string.h, not gdb_string.h.
* xtensa-linux-nat.c: Use string.h, not gdb_string.h.
Since 'struct dwarf_expr_context_funcs::read_addr_from_reg' is now
only used for addresses, we can make it use unpack_pointer. And since
we now have 'struct dwarf_expr_context_funcs'::get_reg_value, there's
no need for speculation about using values here.
Tested on x86_64 Fedora 17.
gdb/
2013-11-18 Pedro Alves <palves@redhat.com>
* dwarf2-frame.c (read_addr_from_reg): Remove stale comment and
use unpack_pointer.
This is to help make it slightly clearer how this method is expected
to extract data from the given register.
gdb/ChangeLog:
* dwarf2expr.h (struct dwarf_expr_context_funcs)
<read_addr_from_reg>: Renames "read_reg".
* dwarf2-frame.c (read_addr_from_reg): Renames "read_reg".
Adjust comment.
(dwarf2_frame_ctx_funcs, execute_stack_op, dwarf2_frame_cache):
Use read_addr_from_reg in place of read_reg.
* dwarf2expr.c (execute_stack_op): Use read_addr_from_reg
in place of read_reg.
* dwarf2loc.c (dwarf_expr_read_addr_from_reg): Renames
dwarf_expr_read_reg.
(dwarf_expr_ctx_funcs): Replace dwarf_expr_read_reg
with dwarf_expr_read_addr_from_reg.
(needs_frame_read_addr_from_reg): Renames needs_frame_read_reg.
(needs_frame_ctx_funcs): Replace needs_frame_read_reg with
needs_frame_read_addr_from_reg.
Consider the following code, compiled at -O2 on ppc-linux:
procedure Increment (Val : in out Float; Msg : String);
The implementation does not really matter in this case). In our example,
this function is being called from a function with Param_1 set to 99.0.
Trying to break inside that function, and running until reaching that
breakpoint yields:
(gdb) b increment
Breakpoint 1 at 0x100014b4: file callee.adb, line 6.
(gdb) run
Starting program: /[...]/foo
Breakpoint 1, callee.increment (val=99.0, val@entry=0.0, msg=...)
at callee.adb:6
6 if Val > 200.0 then
The @entry value for parameter "val" is incorrect, it should be 99.0.
The associated call-site parameter DIE looks like this:
.uleb128 0xc # (DIE (0x115) DW_TAG_GNU_call_site_parameter)
.byte 0x2 # DW_AT_location
.byte 0x90 # DW_OP_regx
.uleb128 0x21
.byte 0x3 # DW_AT_GNU_call_site_value
.byte 0xf5 # DW_OP_GNU_regval_type
.uleb128 0x3f
.uleb128 0x25
The DW_AT_GNU_call_site_value uses a DW_OP_GNU_regval_type
operation, referencing register 0x3f=63, which is $f31,
an 8-byte floating register. In that register, the value is
stored using the usual 8-byte float format:
(gdb) info float
f31 99.0 (raw 0x4058c00000000000)
The current code evaluating DW_OP_GNU_regval_type operations
currently is (dwarf2expr.c:execute_stack_op):
result = (ctx->funcs->read_reg) (ctx->baton, reg);
result_val = value_from_ulongest (address_type, result);
result_val = value_from_contents (type,
value_contents_all (result_val));
What the ctx->funcs->read_reg function does is read the contents
of the register as if it contained an address. The rest of the code
continues that assumption, thinking it's OK to then use that to
create an address/ulongest struct value, which we then re-type
to the type specified by DW_OP_GNU_regval_type.
We're getting 0.0 above because the read_reg implementations
end up treating the contents of the FP register as an integral,
reading only 4 out of the 8 bytes. Being a big-endian target,
we read the high-order ones, which gives us zero.
This patch fixes the problem by introducing a new callback to
read the contents of a register as a given type, and then adjust
the handling of DW_OP_GNU_regval_type to use that new callback.
gdb/ChangeLog:
* dwarf2expr.h (struct dwarf_expr_context_funcs) <read_reg>:
Extend the documentation a bit.
<get_reg_value>: New field.
* dwarf2loc.c (dwarf_expr_get_reg_value)
(needs_frame_get_reg_value): New functions.
(dwarf_expr_ctx_funcs, needs_frame_ctx_funcs): Add "get_reg_value"
callback.
* dwarf2-frame.c (get_reg_value): New function.
(dwarf2_frame_ctx_funcs): Add "get_reg_value" callback.
* dwarf2expr.c (execute_stack_op) <DW_OP_GNU_regval_type>:
Use new callback to compute result_val.
gdb/testsuite/ChangeLog:
* gdb.ada/O2_float_param: New testcase.
The 'bytes_read' change should be obvious. As for the other hunk,
we're passing the address of the signed 'offset' to safe_read_uleb128,
which expects unsigned. Fix it by passing the address of the unsigned
'utmp' instead, like already done on other spots in the file.
gdb/
2013-04-19 Pedro Alves <palves@redhat.com>
* dwarf2-frame.c (execute_cfa_program): Make 'bytes_read' local
unsigned. Pass 'tmp' to safe_read_uleb128 instead of the signed
'offset', and adjust.
const.
* dwarf2read.c (struct dwarf2_section_info) <buffer>: Now const.
(struct die_reader_specs) <buffer>: Likewise.
(die_reader_func_ftype): Make 'info_ptr' const.
(struct line_header) <include_dirs, statement_program_start,
statement_program_end>: Now const.
(struct file_entry) <name>: Likewise.
(struct partial_die_info) <sibling>: Likewise.
(struct dwarf_block) <data>: Likewise.
(dwarf2_read_section): Remove cast.
(dwarf2_get_section_info): Make 'bufp' const.
(read_index_from_section): Constify.
(dw2_get_file_names_reader): Make 'info_ptr' const.
(dw2_get_primary_filename_reader): Likewise.
(read_comp_unit_head): Make 'info_ptr' and return type const.
(read_and_check_comp_unit_head, read_and_check_type_unit_head):
Likewise.
(read_abbrev_offset): Constify.
(dwarf2_create_include_psymtab): Make 'name' const.
(create_debug_types_hash_table): Update.
(read_cutu_die_from_dwo): Make 'result_info_ptr' const.
(init_cutu_and_read_dies, init_cutu_and_read_dies_no_follow):
Constify.
(process_psymtab_comp_unit_reader, build_type_psymtabs_reader)
(load_partial_comp_unit_reader): Make 'info_ptr' const.
(read_comp_units_from_section): Constify.
(peek_abbrev_code, peek_die_abbrev, skip_children, skip_one_die)
(locate_pdi_sibling, load_full_comp_unit_reader): Make 'info_ptr'
const.
(dwarf2_compute_name, setup_type_unit_groups): Constify.
(create_dwo_debug_info_hash_table): Make 'info_ptr' const.
(create_dwp_hash_table, dwarf2_ranges_read)
(dwarf2_record_block_ranges): Constify.
(read_die_and_children, read_die_and_siblings_1)
(read_die_and_siblings): Make 'info_ptr' and 'new_info_ptr'
const.
(read_full_die_1, read_full_die): Make 'info_ptr' const.
(abbrev_table_read_table): Constify.
(load_partial_dies): Make 'info_ptr' const.
(read_partial_die, read_attribute_value, read_attribute): Make
'info_ptr' and return type const.
(read_address, read_initial_length)
(read_checked_initial_length_and_offset, read_offset)
(read_offset_1, read_n_bytes, read_direct_string): Make 'buf'
const.
(read_direct_string): Make 'buf' and return type const.
(read_indirect_string_at_offset, read_indirect_string_from_dwz)
(read_indirect_string): Make return type const.
(read_unsigned_leb128, read_signed_leb128): Make 'buf' const.
(read_addr_index_from_leb128, dwarf2_read_addr_index_reader): Make
'info_ptr' const.
(read_str_index): Make return type const.
(add_include_dir): Make 'include_dir' const.
(add_file_name): Make 'name' const.
(dwarf_decode_line_header): Constify.
(psymtab_include_file_name): Make return type const.
(dwarf_decode_lines_1, dwarf_decode_lines): Constify.
(dwarf2_start_subfile): Make 'filename' const.
(dwarf2_const_value_attr): Make 'bytes' const.
(read_signatured_type_reader): Make 'info_ptr' const.
(decode_locdesc): Constify.
(skip_form_bytes): Make 'bytes', 'buffer_end', and return type
const.
(skip_unknown_opcode): Make 'opcode_definitions', 'mac_ptr',
'mac_end', and return type const.
(dwarf_parse_macro_header): Make 'mac_ptr' and return type const.
(dwarf_decode_macro_bytes): Make 'mac_ptr', 'mac_end', and return
type const.
(per_cu_header_read_in): Constify.
* symfile.h (dwarf2_get_section_info): Update.
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.
* configure.ac (CC_HAS_LONG_LONG): Replace by AC_MSG_ERROR.
* defs.h (LONGEST, ULONGEST): Remove conditionalization for
CC_HAS_LONG_LONG.
* dwarf2-frame.c (DW64_CIE_ID): Likewise.
* dwarf2read.c (extract_cu_value): Remove the function.
(create_cus_from_index_list): Make the return type void, inline the
extract_cu_value caller, include new gdb_static_assert.
(create_cus_from_index): Make the return type void, update the function
comment, update the create_cus_from_index_list caller.
(create_signatured_type_table_from_index): Make the return type void,
inline the extract_cu_value caller, include new gdb_static_assert.
(dwarf2_read_index): Update the create_cus_from_index and
create_signatured_type_table_from_index caller.
* printcmd.c (ui_printf): Remove conditionalizations for
CC_HAS_LONG_LONG.
* config.in: Regenerate.
* configure: Regenerate.
gdb/doc/
* gdbint.texinfo (Host Definition): Remove CC_HAS_LONG_LONG.
The problem is trying to unwind from a function where %ebp is NOT
used as the frame pointer, and the size of the frame changes over
the lifetime of that function.
For instance, trying to unwind past the GNAT runtime function
called system.tasking.rendezvous.timed_selective_wait on x86-linux,
one can get:
(gdb) bt
[...]
#3 0x0805364b in system.tasking.rendezvous.timed_selective_wait ()
#4 0xb7fe5068 in ?? ()
Backtrace stopped: previous frame inner to this frame (corrupt stack?)
Looking at the CFI, we find the following initial instructions...
> DW_CFA_def_cfa: %esp+4 (r4 ofs 4)
> DW_CFA_offset: %eip at cfa-4 (r8 = %eip)
... and the associated FDE:
> 00001be4 00000054 00001be8 FDE cie=00000000 pc=08053310..08053951
[...]
> DW_CFA_advance_loc: 8 to 080534ad
> DW_CFA_def_cfa_offset: 112
> DW_CFA_advance_loc2: 414 to 0805364b
> DW_CFA_def_cfa_offset: 108
[...]
The problem is that the DWARF frame unwinder executed the FDE until
the row for PC == 0x0805364b. But in reality, our program hasn't
executed the instruction at that address yet (it is the return address).
So GDB executed a little too much of the FDE, giving us the wrong
offset for the frame base, and thus the wrong address where %eip
got saved.
This patch fixes the problem by using a more correct PC as the bound
for executing the FDE.
gdb/ChangeLog:
* dwarf2-frame.c (dwarf2_frame_cache): Use
get_frame_address_in_block instead of get_frame_pc as
the bound for executing the frame's FDE.
gdb/testsuite/ChangeLog:
* gdb.ada/rdv_wait: New testcase.
"const gdb_byte *".
(struct dwarf2_fde): Make instructions, end "const gdb_byte *".
(execute_cfa_program): Update to match API of leb128 functions.
(read_1_byte, read_4_bytes, read_8_bytes): Make buf parameter
"const gdb_byte *".
(read_unsigned_leb128, read_signed_leb128): Delete.
(read_initial_length): Change type of buf argument to
"const gdb_byte *".
(read_encoded_value): Update to match API of leb128 functions.
(decode_frame_entry): Change result to "const gdb_byte *", and
similarly for "start" parameter.
(decode_frame_entry_1): Ditto. Use new leb128 reader functions.
(dwarf2_build_frame_info): Change local frame_ptr to
"const gdb_byte *".
* dwarf2expr.c (safe_read_uleb128, safe_read_sleb128): Replaces
read_uleb128, read_sleb128. All callers updated.
(safe_skip_leb128): New function.
(dwarf_block_to_dwarf_reg): Update to match API of leb128 functions.
Call gdb_read_uleb128, gdb_skip_leb128 instead of read_uleb128.
(dwarf_block_to_dwarf_reg_deref): Update to match API of leb128
functions. Call gdb_read_uleb128, gdb_read_sleb128 instead of
read_uleb128, read_sleb128.
(dwarf_block_to_fb_offset, dwarf_block_to_sp_offset): Ditto.
(execute_stack_op): Update to match API of leb128 functions.
* dwarf2expr.h: #include "leb128.h".
(read_uleb128, read_sleb128): Delete.
(gdb_read_uleb128, gdb_read_sleb128, gdb_skip_leb128): New functions.
(safe_read_uleb128, safe_read_sleb128, safe_skip_leb128): Declare.
* dwarf2loc.c (debug_loc_kind): New enum.
(decode_debug_loc_addresses): New function.
(decode_debug_loc_dwo_addresses): New function.
(dwarf2_find_location_expression): Rewrite.
(dwarf2_compile_expr_to_ax): Update to match API of leb128 functions.
(locexpr_describe_location_piece): Ditto.
(disassemble_dwarf_expression): Ditto.
(locexpr_describe_location_1): Ditto.
(loclist_describe_location): Rewrite.
* dwarf2loc.h (dwarf2_loclist_baton): New member "from_dwo".
* dwarf2read.c (die_reader_specs): New member "buffer_end".
(dwarf2_section_buffer_overflow_complaint): Renamed from
dwarf2_macros_too_long_complaint. All callers updated.
(skip_leb128): Delete.
(init_cu_die_reader): Initialize reader->buffer_end.
(skip_one_die): Replace call to skip_leb128 with safe_skip_leb128.
(skip_form_bytes): New arg buffer_end. All callers updated.
Replace call to skip_leb128 with gdb_skip_leb128.
(skip_unknown_opcode): New arg mac_end. All callers updated.
(fill_in_loclist_baton): Initialize baton->from_dwo.
* symfile.c (default_symfile_relocate): Use sectp->owner instead of
objfile->obfd.
* symfile.h (dwarf2_debug_sections): New member addr.
* dwarf2expr.c (execute_stack_op): New case DW_OP_GNU_addr_index.
(ctx_no_get_addr_index): New function.
* dwarf2expr.h (dwarf_expr_context_funcs): New member get_addr_index.
(ctx_no_get_addr_index): Declare.
* dwarf2-frame.c (dwarf2_frame_ctx_funcs): Update.
* dwarf2loc.c (dwarf_expr_get_addr_index): New function.
(dwarf_expr_ctx_funcs): Update.
(needs_get_addr_index): New function.
(needs_frame_ctx_funcs): Update.
* dwarf2loc.h (dwarf2_read_addr_index): Declare.
* dwarf2read.c: #include "gdbcore.h".
(dwarf2_per_objfile): New members addr, dwo_files.
(dwarf2_elf_names): Add entry for addr.
(struct dwo_section_names): New type.
(dwo_section_names): New static global.
(dwarf2_cu): New members dwo_unit, addr_base, have_addr_base.
(dwarf2_per_cu_data): New member is_debug_types, all boolean uses of
old debug_types_section member updated to use this.
Rename member debug_types_section to info_or_types_section,
all uses updated.
(signatured_type): Rename member type_offset to type_offset_in_tu,
all uses updated. New member type_offset_in_section.
(struct dwo_sections): New type.
(struct dwo_unit): New type.
(struct dwo_file): New type.
(die_reader_specs): New member dwo_file.
(dwarf2_locate_sections): Watch for .debug_addr.
(zlib_decompress_section): Use sectp->owner instead of objfile->obfd.
(dwarf2_read_section): Get bfd of section from bfd's asection,
instead of objfile.
(create_cus_from_index): Initialize the_cu->info_or_types_section.
(create_signatured_type_table_from_index): Initialize
sig_type->info_or_types_section.
(dw2_get_file_names): Statement lists for type units with DWO files
live in the DWO file.
(create_debug_types_hash_table): New function.
(create_all_type_units): Rewrite.
(init_cu_die_reader): New arg dwo_file, all callers updated.
(init_and_read_dies_worker): Get section from
this_cu->info_or_types_section. Set sig_type->type_offset_in_section.
Watch for DW_AT_GNU_dwo_name and if present lookup the file and
continue reading the CU/TU from there.
(init_cutu_and_read_dies_no_follow): New arg dwo_file, all callers
updated. Get section from this_cu->info_or_types_section.
(create_all_comp_units): Initialize this_cu->info_or_types_section.
(skip_one_die): New cases DW_FORM_GNU_addr_index,
DW_FORM_GNU_str_index.
(hash_dwo_file, eq_dwo_file): New functions.
(allocate_dwo_file_hash_table): New function.
(hash_dwo_unit, eq_dwo_unit): New functions.
(allocate_dwo_unit_table): New function.
(dwarf2_locate_dwo_sections): New function.
(struct create_dwo_info_table_data): New type.
(create_debug_info_hash_table_reader): New function.
(create_debug_info_hash_table): New function.
(try_open_dwo_file, open_dwo_file, init_dwo_file): New function.
(lookup_dwo_file): New function.
(lookup_dwo_comp_unit, lookup_dwo_type_unit): New functions.
(free_dwo_file, free_dwo_file_cleanup): New functions.
(free_dwo_file_from_slot, free_dwo_files): New functions.
(dwarf2_get_pc_bounds): Handle DW_FORM_GNU_addr_index.
(dwarf2_record_block_ranges): Ditto.
(read_partial_die): Ditto.
(process_enumeration_scope): Update to use type_offset_in_section.
(read_full_die_1): New function.
(read_full_die): Rewrite.
(read_attribute_value): New cases DW_FORM_GNU_addr_index,
DW_FORM_GNU_str_index.
(read_addr_index_1, read_addr_index): New functions.
(read_addr_index_from_leb128): New function.
(struct dwarf2_read_addr_index_data): New type.
(dwarf2_read_addr_index_reader): New function.
(dwarf2_read_addr_index): New function.
(read_str_index): New function.
(leb128_size): New function.
(dwarf_decode_line_header): Delete arg abfd, all callers updated.
If processing a type unit from a DWO file, get the line section
from the DWO file.
(var_decode_location): Watch for DW_OP_GNU_addr_index.
(dwarf2_const_value_attr): New cases DW_FORM_GNU_addr_index,
DW_FORM_GNU_str_index.
(lookup_die_type): Check whether section offset of type's die is
known before looking it up. Remove assert. Condition can
legimately happen for inter-cu type references.
(dwarf_attr_name): Handle Fission attributes.
(dwarf_form_name): Handle Fission forms.
(dump_die_shallow): New cases DW_FORM_GNU_addr_index,
DW_FORM_GNU_str_index.
(follow_die_sig): Update to use type_offset_in_section.
(decode_locdesc): New case DW_OP_GNU_addr_index.
(skip_form_bytes): New cases DW_FORM_GNU_addr_index,
DW_FORM_GNU_str_index.
(cu_debug_loc_section): New function.
(fill_in_loclist_baton, dwarf2_symbol_mark_computed): Call it.
(dwarf2_per_objfile_free): Unmap .debug_addr section.
Free DWO files if present.
* xcoffread.c (dwarf2_xcoff_names): Add .debug_addr.
testsuite/
* gdb.dwarf2/dw2-intercu.S (.Ltype_int2_in_cu2): Renamed from
.Ltype_int_in_cu2. Use name "int2" instead of "int".
All uses updated.
* gdb.dwarf2/dw2-intercu.exp: Add "ptype int2" ahead of
"ptype func_cu1" to expand cu2 before cu1.
Implement basic support for DW_TAG_GNU_call_site.
* block.c: Include gdbtypes.h and exceptions.h.
(call_site_for_pc): New function.
* block.h (call_site_for_pc): New declaration.
* defs.h: Include hashtab.h.
(make_cleanup_htab_delete, core_addr_hash, core_addr_eq): New
declarations.
* dwarf2-frame.c (dwarf2_frame_ctx_funcs): Install
ctx_no_push_dwarf_reg_entry_value.
* dwarf2expr.c (read_uleb128, read_sleb128): Support R as NULL.
(dwarf_block_to_dwarf_reg): New function.
(execute_stack_op) <DW_OP_GNU_entry_value>: Implement it.
(ctx_no_push_dwarf_reg_entry_value): New function.
* dwarf2expr.h (struct dwarf_expr_context_funcs): New field
push_dwarf_reg_entry_value.
(ctx_no_push_dwarf_reg_entry_value, dwarf_block_to_dwarf_reg): New
declarations.
* dwarf2loc.c: Include gdbcmd.h.
(dwarf_expr_ctx_funcs): New forward declaration.
(entry_values_debug, show_entry_values_debug, call_site_to_target_addr)
(dwarf_expr_reg_to_entry_parameter)
(dwarf_expr_push_dwarf_reg_entry_value): New.
(dwarf_expr_ctx_funcs): Install dwarf_expr_push_dwarf_reg_entry_value.
(dwarf2_evaluate_loc_desc_full): Handle NO_ENTRY_VALUE_ERROR.
(needs_dwarf_reg_entry_value): New function.
(needs_frame_ctx_funcs): Install it.
(_initialize_dwarf2loc): New function.
* dwarf2loc.h (entry_values_debug): New declaration.
* dwarf2read.c (struct dwarf2_cu): New field call_site_htab.
(read_call_site_scope): New forward declaration.
(process_full_comp_unit): Copy call_site_htab.
(process_die): Support DW_TAG_GNU_call_site.
(read_call_site_scope): New function.
(dwarf2_get_pc_bounds): Support NULL HIGHPC.
(dwarf_tag_name): Support DW_TAG_GNU_call_site.
(cleanup_htab): Delete.
(write_psymtabs_to_index): Use make_cleanup_htab_delete instead of it.
* exceptions.h (enum errors): New NO_ENTRY_VALUE_ERROR.
* gdb-gdb.py (StructMainTypePrettyPrinter): Support
FIELD_LOC_KIND_DWARF_BLOCK.
* gdbtypes.h (enum field_loc_kind): New entry
FIELD_LOC_KIND_DWARF_BLOCK.
(struct main_type): New loc entry dwarf_block.
(struct call_site, FIELD_DWARF_BLOCK, SET_FIELD_DWARF_BLOCK)
(TYPE_FIELD_DWARF_BLOCK): New.
* python/py-type.c: Include dwarf2loc.h.
(check_types_equal): Support FIELD_LOC_KIND_DWARF_BLOCK. New
internal_error call on unknown FIELD_LOC_KIND.
* symtab.h (struct symtab): New field call_site_htab.
* utils.c (do_htab_delete_cleanup, make_cleanup_htab_delete)
(core_addr_hash, core_addr_eq): New functions.
gdb/testsuite/
Implement basic support for DW_TAG_GNU_call_site.
* gdb.arch/Makefile.in (EXECUTABLES): Add amd64-entry-value.
* gdb.arch/amd64-entry-value.cc: New file.
* gdb.arch/amd64-entry-value.exp: New file.
We don't need to read the .eh_frame section from the separate
object files, because this data is already present in the
main executable (it needs to, or the program wouldn't work).
We discovered this investigating a problem with the 'next' command,
which was due to unwind failures, which came from the fact that
the .eh_frame was incorrectly relocated.
gdb/ChangeLog (Tristan Gingold):
* dwarf2-frame.c (dwarf2_build_frame_info): Do not load .eh_frame
section in separate object files.
* symfile.h (enum dwarf2_section_enum): New type.
(dwarf2_get_section_info): New prototype.
* dwarf2read.c (dwarf2_get_section_info): Replace parameter
section_name by sect. Use a switch to select the info.
* dwarf2-frame.c (warf2_get_section_info): Remove prototype.
(dwarf2_build_frame_info): Adjust calls to dwarf2_get_section_info.
* 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.
Throughout, call read_encoded_value with ptr_size rather than addr_size.
(decode_frame_entry_1): Remove redundant setting of
addr_size. Call gdbarch_dwarf2_addr_size rather than gdbarch_ptr_bit
to determine addr_size in Dwarf versions < 4. Set ptr_size dependent
on examined frame section. Add comment to explain why.
* gdbarch.sh (dwarf2_addr_size): Define as variable. Add lengthy
comment to explain usage.
* gdbarch.c: Regenerate.
* gdbarch.h: Regenerate.
* xstormy16-tdep.c (xstormy16_gdbarch_init): Set dwarf2_addr_size to 4.
* dwarf2expr.h (struct dwarf_value_location): Use ULONGEST as type
of stack values.
(struct dwarf_expr_piece): Rename "expr" member to "mem". Add new
"value" member.
(dwarf_expr_push): Change input type to ULONGEST.
(dwarf_expr_fetch): Change return type to ULONGEST.
(dwarf_expr_fetch_address): Add prototype.
(dwarf2_read_address): Remove prototype.
* dwarf2expr.c (dwarf_expr_push): Use ULONGEST as type of stack values.
Truncate stack values to ctx->addr_size bytes.
(dwarf_expr_fetch): Change return value to ULONGEST.
(dwarf_expr_fetch_address): New function.
(add_piece): Use dwarf_expr_fetch_address instead of dwarf_expr_fetch
when appropriate. Update for struct dwarf_expr_piece changes.
(dwarf2_read_address): Remove.
(unsigned_address_type): Remove.
(signed_address_type): Remove.
(execute_stack_op): Use dwarf_expr_fetch_address instead of
dwarf_expr_fetch when appropriate. Use ULONGEST as type of stack
values. Perform operations on ULONGEST instead of on GDB values,
sign-extending from ctx->addr_size bytes as needed. Read DW_OP_addr
values and DW_OP_deref results as unsigned integers.
* dwarf2loc.c (read_pieced_value): Update for struct dwarf_expr_piece
changes.
(write_pieced_value): Likewise.
(dwarf2_evaluate_loc_desc): Use dwarf_expr_fetch_address instead of
dwarf_expr_fetch when appropriate.
(compile_dwarf_to_ax): Read DW_OP_addr values as unsigned integers.
* dwarf2-frame.c (execute_stack_op): Use dwarf_expr_fetch_address
instead of dwarf_expr_fetch when appropriate.
testsuite/ChangeLog:
* gdb.cell/dwarfaddr.exp: New file.
* gdb.cell/dwarfaddr.S: New file.
Ulrich Weigand