This patch creates a new function called "ada_val_print_string"
whose code is directly extracted out of ada_val_print_array.
The extracted code is then replaced by a call to this new function,
followed by a "return". The return avoids the need for an "else"
branch, with the associated block nesting. The latter is not really
terrible in this case, but it seems more readable this way.
gdb/ChangeLog:
* ada-valprint.c (ada_val_print_string): New function,
extracted from ada_val_print_array.
(ada_val_print_array): Replace extracted code by call
to ada_val_print_string followed by a return. Move
"else" branch to the function's top block.
This patch moves ada_val_print_array to group it with the other
ada_val_print_* function which are being called by ada_val_print_1.
Since this function is in the same situation, it is more logical
to move it within that group.
It also rationalizes the function's prototype to match the prototype
of the other ada_val_print_* routines.
gdb/ChangeLog:
* ada-valprint.c (ada_val_print_array): Move implementation
down. Rename parameter "offset" and "val" into "offset_aligned"
and "original_value" respectively. Add parameter "offset".
The logic as currently implemented in this function was a little
difficult to follow, due to the nested of if/else conditions,
but most of the time, the "else" block was very simple. So this
patch re-organizes the code to use fewer levels of nesting by
using return statements, and writing the code as a sequence of
"if something simple, then handle it and return" blocks.
While touching this code, this patch changes the cryptic "???"
printed when trying to print a reference pointing to an undefined
type. This should only ever happen if the debugging information
was corrupted or improperly read. But in case that happens, we now
print "<ref to undefined type>" instead. This is more in line
with how we print other conditions such as optimized out pieces,
or synthetic pointers.
gdb/ChangeLog:
* ada-valprint.c (ada_val_print_ref): Rewrite by mostly
re-organizing the code. Change the "???" message printed
when target type is a TYPE_CODE_UNDEF into
"<ref to undefined type>".
The function print_record is a fairly small and straightforward
function which is only called from one location. So this patch
inlines the code at the point of call.
One small advantage is that the context of use of this patch has
now become such that we can assume that TYPE is not a typedef,
nor an enum. So thhe call to ada_check_typedef is unnecessary,
and this patch removes it.
gdb/ChangeLog:
* ada-valprint.c (print_record): Delete, implementation inlined...
(ada_val_print_struct_union): ... here. Remove call to
ada_check_typedef in inlined implementation.
The idea of this patch is that it's hard to have a global view of
ada_val_print_1 because its body spans over too many lines. Also,
each individual "case" block within the giant "switch" can be hard
to isolate if spanning over multiple pages as well.
gdb/ChangeLog:
* ada-valprint.c (ada_val_print_gnat_array): New function,
extracted from ada_val_print_1;
(ada_val_print_ptr, ada_val_print_num, ada_val_print_enum)
(ada_val_print_flt, ada_val_print_struct_union)
(ada_val_print_ref): Likewise.
(ada_val_print_1): Delete variables i and elttype.
Replace extracted-out code by call to corresponding
new functions.
I am not sure why this function was called in the first place, but
it disrupts the printing flow when in GDB/MI mode, ending the current
console stream output, and starting a new one. It's not clear whether,
with the code as currently written, the problem is actually visible
or only latent. But, it becomes visible when we replace one of the
"return" statements in the "switch" block just above by a "break"
statement (this is something I'd like to do, and what made me realize
the problem). With the gdb_flush call (after having replaced the
"return" statement as explained above), we get:
% gdb -q -i=mi ada_prg
(gdb)
print 1
&"print 1\n"
!! -> ~"$1 = 1"
!! -> ~"\n"
^done
With the gdb_flush call removed, we now get the entire output into
a single stream.
(gdb)
print 1
&"print 1\n"
~"$1 = 1"
~"\n"
^done
gdb/ChangeLog:
* ada-valprint.c (ada_val_print_1): Remove call to gdb_flush.
This is to standardize a little bit how printing is done, and in
particular make sure that everyone goes through val_print when
printing sub-objects. This helps making sure that standard features
handled by val_print get activated when expected.
gdb/ChangeLog:
* ada-valprint.c (ada_val_print_1): Replace calls to
ada_val_print_1 by calls to val_print.
This is to help calling val_print. We would like to be more systematic
in calling val_print when printing, because it allows us to make sure
we take advantage of the standard features such as pretty-printing
which are handled by val_print.
gdb/ChangeLog:
* ada-valprint.c (ada_val_print_1): Add parameter "language".
Update calls to self accordingly. Replace calls to c_val_print
by calls to val_print.
Advance function declarations add to the maintenance cost, since
any update to the function prototype needs to be made twice.
For static functions, this is not necessary, and this patch
reorders the function so as to reduce the use of such advanche
declarations.
gdb/ChangeLog:
* ada-valprint.c (print_record): Delete declaration.
(adjust_type_signedness, ada_val_print_1): Likewise.
(ada_val_print): Move function implementation down.
(print_variant_part, print_field_values, print_record):
Move function implementation up.
Consider the following declarations:
typedef long our_time_t;
our_time_t current_time = 1384395743;
The purpose of this patch is to allow the use of a pretty-printer
for variables of type our_time_t. Normally, pretty-printing sniffers
use the tag name in order to determine which, if any, pretty-printer
should be used. But in the case above, the tag name is not set, since
it does not apply to integral types.
This patch extends the gdb.Type list of attributes to also include
the name of the type, thus allowing the sniffer to match against
that name. With that change, I was able to write a pretty-printer
which displays our variable as follow:
(gdb) print current_time
$1 = Thu Nov 14 02:22:23 2013 (1384395743)
gdb/ChangeLog:
* python/py-type.c (typy_get_name): New function.
(type_object_getset): Add entry for attribute "name".
* NEWS: Add entry mentioning this new attribute.
gdb/doc/ChangeLog:
* gdb.texinfo (Types In Python): Document new attribute Types.name.
gdb/testsuite:
* gdb.python/py-pp-integral.c: New file.
* gdb.python/py-pp-integral.py: New file.
* gdb.python/py-pp-integral.exp: New file.
Tested on x86_64-linux.
This patch removes the if statement and the comments together.
gdb:
2014-01-07 Yao Qi <yao@codesourcery.com>
* gnu-nat.c (set_exceptions_cmd): Remove an empty body 'if'
statement.
This patch fixes the following error.
../../../git/gdb/gnu-nat.c: In function 'info_port_rights':
../../../git/gdb/gnu-nat.c:3083:11: error: passing argument 1 of 'parse_to_comma_and_eval' from incompatible pointer type [-Werror]
In file included from ../../../git/gdb/breakpoint.h:23:0,
from ../../../git/gdb/inferior.h:37,
from ../../../git/gdb/gnu-nat.c:55:
../../../git/gdb/value.h:763:22: note: expected 'const char **' but argument is of type 'char **'
gdb:
2014-01-07 Yao Qi <yao@codesourcery.com>
* gnu-nat.c (info_port_rights): Add qualifier const to
argument args.
This patch fixes the following error:
../../../git/gdb/gnu-nat.c: In function 'trace_me':
../../../git/gdb/gnu-nat.c:2106:8: error: old-style function definition [-Werror=old-style-definition]
gdb:
2014-01-07 Yao Qi <yao@codesourcery.com>
* gnu-nat.c (trace_me): Use 'void' for empty argument list.
inf_tid_to_proc is not defined at all. This patch is to remove its
declaration.
gdb:
2014-01-07 Yao Qi <yao@codesourcery.com>
* gnu-nat.c (inf_tid_to_proc): Remove declaration.
This patch fixes this error below by declaring _initialize_gnu_nat.
../../../git/gdb/gnu-nat.c:3447:1: error: no previous prototype for '_initialize_gnu_nat' [-Werror=missing-prototypes]
gdb:
2014-01-07 Yao Qi <yao@codesourcery.com>
* gnu-nat.c (_initialize_gnu_nat): Declare.
This patch changes the return type of gdbarch_byte_order and
gdbarch_byte_order_for_code, from 'int' to 'enum bfd_endian'.
gdb:
2014-01-07 Yao Qi <yao@codesourcery.com>
* gdbarch.sh (byte_order, byte_order_for_code): Change type to
'enum bfd_endian'.
(struct gdbarch_info) <byte_order>: Change type to
'enum bfd_endian'.
<byte_order_for_code>: Likewise.
* gdbarch.c, gdbarch.h: Regenerated.
This removes the last uses of the obsolete CONST macro from the tree.
I'm checking this in. Tested by rebuilding.
2014-01-06 Tom Tromey <tromey@redhat.com>
* doublest.c (convert_doublest_to_floatformat): Use const, not
CONST.
* somread.c (som_symtab_read): Likewise.
gdb/ChangeLog:
* top.c (print_gdb_version): Set copyright year to 2014.
gdb/gdbserver/ChangeLog:
* gdbserver.c (gdbserver_version): Set copyright year to 2014.
* gdbreplay.c (gdbreplay_version): Likewise.
Continuing my series of fixes on the SystemTap SDT support for the
ARM/AArch64 architectures, this patch now extends how ARM's SDT specific
parser handles literal numbers (immediates).
Currently, it only accepts "#" as the prefix. However, according to
"info '(as) ARM-Chars'", expressions can also have "$" and nothing as a
prefix. This patch extends the parser to accept those options.
2013-12-28 Sergio Durigan Junior <sergiodj@redhat.com>
* arm-linux-tdep.c (arm_stap_is_single_operand): Accept "$" as a
literal prefix. Also accept no prefix at all.
(arm_stap_parse_special_token): Likewise.
(arm_linux_init_abi): Likewise.
This commit implements the needed bits for SystemTap SDT probe support
on AArch64 architectures.
First, I started by looking at AArch64 assembly specification and
filling the necessary options on gdbarch's stap machinery in order to
make the generic asm parser (implemented in stap-probe.c) recognize
AArch64's asm.
After my last patch for the SystemTap SDT API, which extends it in order
to accept multiple prefixes and suffixes, this patch became simpler. I
also followed Marcus suggestion and did not shared code between 32- and
64-bit ARM.
Tom asked me in a previous message how I did my tests. I believe I
replied that, but just in case: I ran the tests on
gdb.base/stap-probe.exp by hand. I also managed to run the tests on
real hardware, and they pass without regressions.
2013-12-28 Sergio Durigan Junior <sergiodj@redhat.com>
PR tdep/15653
* NEWS: Mention SystemTap SDT probe support for AArch64 GNU/Linux.
* aarch64-linux-tdep.c: Include necessary headers for parsing of
SystemTap SDT probes.
(aarch64_stap_is_single_operand): New function.
(aarch64_stap_parse_special_token): Likewise.
(aarch64_linux_init_abi): Declare SystemTap SDT probe argument
prefixes and suffixes. Initialize gdbarch with them.
This patch does some basic cleanups on the SystemTap SDT probes API. It
removes spurious newlines, brackets, reindents some code, and do
explicit checks for NULL, NUL, and 0 where applicable.
2013-12-23 Sergio Durigan JUnior <sergiodj@redhat.com>
* stap-probe.c (struct stap_probe) <args_parsed>: Add comment.
(stap_is_generic_prefix): Delete extra brackets. Reindent.
(stap_parse_register_operand): Remove spurious newlines. Simplify
code to parse special token.
(stap_parse_argument_conditionally): Add gdb_assert.
(stap_parse_argument_1): Likewise. Explicitly check for NULL and
NUL.
(stap_parse_probe_arguments): Likewise.
(handle_stap_probe): Likewise. Reindent code.
(get_stap_base_address): Explicitly check for NULL.
(stap_get_probes): Likewise. Reindent code.
(stap_relocate): Explicitly check for 0.
(stap_gen_info_probes_table_values): Likewise.
PREFIX_ADDR isn't a prefix to opcode. This patch masks out PREFIX_ADDR
when adding prefix to opcode.
PR gdb/16305
* i386-tdep.c (i386_process_record): Mask out PREFIX_ADDR when
adding prefix to opcode.
64-bit mode doesn't use 16-bit address. We should always check SIB byte
for address in 64-bit mode.
PR gdb/16304
* i386-tdep.c (i386_record_lea_modrm_addr): Don't use 16-bit
address in 64-bit mode.
When there is ADDR32 prefix in 64-bit mode, we should zero-extend
address from 32-bit to 64-bit.
PR gdb/16304
* i386-tdep.c (i386_record_lea_modrm_addr): Zero-extend 32-bit
address to 64-bit in 64-bit mode.
X32 Linux system calls are diffferent from amd64 Linux system calls in
system call numbers as well as parameter types/values. This patch adds
amd64_x32_linux_record_tdep and amd64_x32_syscall for x32.
PR gdb/16304
* amd64-linux-tdep.c (amd64_canonicalize_syscall): Handle x32
system calls.
(amd64_x32_linux_record_tdep): New.
(amd64_linux_syscall_record_common): New function.
(amd64_linux_syscall_record): Call
amd64_linux_syscall_record_common with amd64_linux_record_tdep.
(amd64_x32_linux_syscall_record): Call
amd64_linux_syscall_record_common with
amd64_x32_linux_record_tdep.
(amd64_linux_init_abi_common): Move amd64_linux_record_tdep
initialization and tdep->i386_syscall_record setup to ...
(amd64_linux_init_abi): Here.
(amd64_x32_linux_init_abi): Initialize
amd64_x32_linux_record_tdep. Set tdep->i386_syscall_record to
amd64_x32_linux_syscall_record.
* amd64-linux-tdep.h (amd64_x32_syscall): New enum.
This patch extends the current generic parser for SystemTap SDT probe
arguments. It can be almost considered a cleanup, but the main point of
it is actually to allow the generic parser to accept multiple prefixes
and suffixes for the its operands (i.e., integers, register names, and
register indirection).
I have chosen to implement this as a list of const strings, and declare
this list as "static" inside each target's method used to initialize
gdbarch.
This patch is actually a preparation for an upcoming patch for ARM,
which implements the support for multiple integer prefixes (as defined
by ARM's asm spec). And AArch64 will also need this, for the same
reason.
This patch was regtested on all architectures that it touches (i.e.,
i386, x86_64, ARM, PPC/PPC64, s390x and IA-64). No regressions were found.
2013-12-19 Sergio Durigan Junior <sergiodj@redhat.com>
* amd64-tdep.c (amd64_init_abi): Declare SystemTap SDT probe
argument prefixes and suffixes. Initialize gdbarch with them.
* arm-linux-tdep.c (arm_linux_init_abi): Likewise.
* gdbarch.c: Regenerate.
* gdbarch.h: Regenerate.
* gdbarch.sh (stap_integer_prefix, stap_integer_suffix)
(stap_register_prefix, stap_register_suffix)
(stap_register_indirection_prefix)
(stap_register_indirection_suffix): Declare as "const char *const
*" instead of "const char *". Adjust printing function. Rename
all of the variables to the plural.
(pstring_list): New function.
* i386-tdep.c (i386_elf_init_abi): Declare SystemTap SDT probe
argument prefixes and suffixes. Initialize gdbarch with them.
* ia64-linux-tdep.c (ia64_linux_init_abi): Likewise.
* ppc-linux-tdep.c (ppc_linux_init_abi): Likewise.
* s390-linux-tdep.c (s390_gdbarch_init): Likewise.
* stap-probe.c (stap_is_generic_prefix): New function.
(stap_is_register_prefix): Likewise.
(stap_is_register_indirection_prefix): Likewise.
(stap_is_integer_prefix): Likewise.
(stap_generic_check_suffix): Likewise.
(stap_check_integer_suffix): Likewise.
(stap_check_register_suffix): Likewise.
(stap_check_register_indirection_suffix): Likewise.
(stap_parse_register_operand): Remove unecessary declarations for
variables holding prefix and suffix information. Use the new
functions listed above for checking for prefixes and suffixes.
(stap_parse_single_operand): Likewise.
Code rationale
==============
by: Gabriel Krisman Bertazi
This is a fix for bug 16297. The problem occurs when the user attempts
to catch any syscall 0 (such as syscall read on Linux/x86_64). GDB was
not able to catch the syscall and was missing the breakpoint.
Now, breakpoint_hit_catch_syscall returns immediately when it finds the
correct syscall number, avoiding a following check for the end of the
search vector, that returns a no hit if the syscall number was zero.
Testcase rationale
==================
by: Sergio Durigan Junior
This testcase is a little difficult to write. By doing a quick
inspection at the Linux source, one can see that, in many targets, the
syscall number 0 is restart_syscall, which is forbidden to be called
from userspace. Therefore, on many targets, there's just no way to test
this safely.
My decision was to take the simpler route and just adds the "read"
syscall on the default test. Its number on x86_64 is zero, which is
"good enough" since many people here do their tests on x86_64 anyway and
it is a popular architecture.
However, there was another little gotcha. When using "read" passing 0
as the third parameter (i.e., asking it to read 0 bytes), current libc
implementations could choose not to effectively call the syscall.
Therefore, the best solution was to create a temporary pipe, write 1
byte into it, and then read this byte from it.
gdb/ChangeLog
2013-12-19 Gabriel Krisman Bertazi <gabriel@krisman.be>
PR breakpoints/16297
* breakpoint.c (breakpoint_hit_catch_syscall): Return immediately
when expected syscall is hit.
gdb/testsuite/ChangeLog
2013-12-19 Sergio Durigan Junior <sergiodj@redhat.com>
PR breakpoints/16297
* gdb.base/catch-syscall.c (read_syscall, pipe_syscall)
(write_syscall): New variables.
(main): Create a pipe, write 1 byte in it, and read 1 byte from
it.
* gdb.base/catch-syscall.exp (all_syscalls): Include "pipe,
"write" and "read" syscalls.
(fill_all_syscalls_numbers): Improve the way to obtain syscalls
numbers.
Now that struct serial_ops is const everywhere, we can easily turn the
instances into globals. This patch implements this idea.
On the one hand I think this is nicer since it makes a bit more data
readonly and slightly reduces allocations. On the other hand it
reduces readability somewhat.
If the readability is a concern to anyone I was thinking I could write
a macro that conditionally uses GCC's designated initializer
extension.
Tested by rebuilding on x86-64 Fedora 18, both natively and using the
mingw cross tools.
2013-12-19 Tom Tromey <tromey@redhat.com>
* ser-unix.c (hardwire_ops): New global.
(_initialize_ser_hardwire): Use it.
* ser-tcp.c (tcp_ops): New global.
(_initialize_ser_tcp): Use it.
* ser-pipe.c (pipe_ops): New global.
(_initialize_ser_pipe): Use it.
* ser-mingw.c (hardwire_ops, tty_ops, pipe_ops, tcp_ops): New
globals.
(_initialize_ser_windows): Use them.
I noticed that the serial_ops vtable is not const, but really it ought
to be.
This patch constifies it, removing the only mutable field in the
process.
Tested by rebuilding on x86-64 Fedora 18, both natively and using the
mingw cross tools.
2013-12-19 Tom Tromey <tromey@redhat.com>
* serial.c (serial_ops_p): New typedef.
(serial_ops_list): Now a VEC.
(serial_interface_lookup): Return const. Use VEC_iterate.
(serial_add_interface): Make parameter const.
(serial_open): Update.
(serial_fdopen_ops): Make 'ops' const.
(serial_pipe): Update.
* ser-tcp.c (_initialize_ser_tcp): Update.
* ser-pipe.c (_initialize_ser_pipe): Update.
* ser-unix.c (_initialize_ser_hardwire): Update.
* ser-mingw.c (_initialize_ser_windows): Update.
* ser-go32.c (dos_ops): Now const. Update.
* serial.h (struct serial) <ops>: Now const.
(struct serial_ops) <next>: Remove.
(serial_add_interface): Make parameter const.
* aarch64-linux-nat.c (aarch64_linux_set_debug_regs): Set
iov.iov_len with the real length in use.
gdb/gdbserver/
* linux-aarch64-low.c (aarch64_linux_set_debug_regs): Set
iov.iov_len with the real length in use.
This patch adds a typedef target_xfer_partial_ftype. When we change
the signature of xfer_partial functions (for example, adding a new
parameter), we don't have to modify all of their declarations.
This patch also updates the type of parameters of target_xfer_partial
from "void *" to "gdb_byte *".
gdb:
2013-12-18 Yao Qi <yao@codesourcery.com>
* target.h (target_xfer_partial_ftype): New typedef.
(target_xfer_partial): Update declaration.
* auxv.h (memory_xfer_auxv): Likewise.
* ia64-hpux-nat.c (super_xfer_partial): Likewise.
* ia64-linux-nat.c (super_xfer_partial): Likewise.
* linux-nat.c (super_xfer_partial): Likewise.
* procfs.c (procfs_xfer_partial): Likewise.
* record-full.c (record_full_beneath_to_xfer_partial):
(tmp_to_xfer_partial): Likewise.
* sparc-nat.c (inf_ptrace_xfer_partial): Likewise.
* target.c (default_xfer_partial): Likewise.
(current_xfer_partial): Likewise.
(target_xfer_partial): Change parameter type to 'gdb_byte *'.
I notice that two lines of a recent changelog entry are not prefixed
with tab. They are prefixed with a space and a tab. This patch
is to remove the space.
gdb:
2013-12-18 Yao Qi <yao@codesourcery.com>
* ChangeLog: Fix the format of one entry.
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.
https://sourceware.org/ml/gdb-patches/2013-12/msg00144.html
The vector of unavailable parts of a value is currently byte based. Given
that we can model a value down to the bit level, we can potentially loose
information with the current implementation. After this patch we model the
unavailable information in bits.
gdb/ChangeLog
* dwarf2loc.c (read_pieced_value): Mark bits, not bytes
unavailable, use correct bit length.
* value.c (struct value): Extend comment on unavailable to
indicate that it is bit based.
(value_bits_available): New function.
(value_bytes_available): Call value_bits_available.
(value_entirely_available): Check against the bit length, not byte
length.
(mark_value_bits_unavailable): New function.
(mark_value_bytes_unavailable): Move contents to
mark_value_bits_unavailable, call to same.
(memcmp_with_bit_offsets): New function.
(value_available_contents_bits_eq): New function, takes the
functionality from value_available_contents_eq but uses
memcmp_with_bit_offsets now, and is bit not byte based.
(value_available_contents_eq): Move implementation into
value_available_contents_bits_eq, call to same.
(value_contents_copy_raw): Work on bits, not bytes.
(unpack_value_bits_as_long_1): Check availability in bits, not
bytes.
* value.h (value_bits_available): Declare new function.
(mark_value_bits_unavailable): Declare new function.
gdb/testsuite/ChangeLog
* gdb.trace/unavailable-dwarf-piece.c: New file.
* gdb.trace/unavailable-dwarf-piece.exp: New file.
Like on GNU/Linux (linux-thread-db.c), the Solaris solaris-threads
target (handles libthread_db.so) shouldn't be pushed when remote
debugging.
This uses the same predicate used by linux-thread-db.c.
gdb/
2013-12-16 Pedro Alves <palves@redhat.com>
PR 16329
* sol-thread.c (check_for_thread_db): If the target can't run or
isn't a core, return without pushing.
This reverts commit 07293be448, as it
causes an unintended change of behavior with GDB/MI's =library-loaded
events: The host-name="<path>" part of the event is now showing the
target-side path instead of the host-side path.
This revert affects Darwin and AIX systems, however, where the BFD
is either artificial or icomplete, leading to the outputt of
"info shared" not containing the information we'd like. For instance,
on Darwin, we would see:
(top-gdb) info shared
From To Syms Read Shared Object Library
0x00007fff8d060de4 0x00007fff8d09ce1f Yes (*) i386:x86-64
0x00007fff8af08b10 0x00007fff8b1c6f73 Yes (*) i386:x86-64
To compensate for that, we overwrite the filename of the associated bfd.
gdb/ChangeLog:
Revert the following commit:
* solib.c (solib_map_sections): Remove code overwriting
SO->SO_NAME with the bfd's filename.
Make the following changes required after the revert above:
* solib-aix.c (solib_aix_bfd_open): Set the filename of the
returned bfd to a copy of the synthetic pathname.
* solib-darwin.c (darwin_bfd_open): Set the filename of the
returned bfd to a copy of PATHNAME.
This function has the following code:
elt_type = type;
for (i = n; i > 1; i--)
elt_type = TYPE_TARGET_TYPE (type);
For multi-dimension arrays, the code above tries to find the array
type corresponding to the dimension we're trying to inspect.
The problem is that, past the second dimension, the loop does
nothing other than repeat the first iteration. There is a little
thinko where it got the TYPE_TARGET_TYPE of TYPE instead of ELT_TYPE!
To my surprise, I was unable to produce an Ada exemple that demonstrated
the problem. That's because the examples I created all trigger a parallel
___XA type which we then use in place of the ELT_TYPE in order to
determine the bounds - see the code that immediately follows our
loop above:
index_type_desc = ada_find_parallel_type (type, "___XA");
ada_fixup_array_indexes_type (index_type_desc);
if (index_type_desc != NULL)
[...]
So, in order to avoid depending on an Ada example where the compiler
can potentially decide one way or the other, I decided to use an
artificial example, written in C. With ...
int multi[1][2][3];
... forcing the language to Ada, and trying to print the 'last,
we get:
(gdb) p multi'last(1)
$1 = 0
(gdb) p multi'last(2)
$2 = 1
(gdb) p multi'last(3)
$3 = 1 <<<--- This should be 2!
Additionally, I noticed that a couple of check_typedef's were missing.
This patch adds them. And since the variable in question only gets
used within an "else" block, I moved the variable declaration and
use inside that block - making it clear what the scope of the variable
is.
gdb/ChangeLog:
* ada-lang.c (ada_array_bound_from_type): Move the declaration
and assignment of variable "elt_type" inside the else block
where it is used. Add two missing check_typedef calls.
Fix bug where we got TYPE's TYPE_TARGET_TYPE, where in fact
we really wanted to get ELT_TYPE's TYPE_TARGET_TYPE.
gdb/testsuite/ChangeLog:
* gdb.ada/arraydim: New testcase.
PR python/16113
* NEWS (Python Scripting): Add entry for the new feature and the
new attribute of gdb.Field objects.
* python/py-type.c (gdbpy_is_field): New function
(convert_field): Add 'parent_type' attribute to gdb.Field
objects.
* python/py-value.c (valpy_getitem): Allow subscript value to be
a gdb.Field object.
(value_has_field): New function
(get_field_flag): New function
* python/python-internal.h (gdbpy_is_field): Add declaration.
testsuite/
* gdb.python/py-value-cc.cc: Improve test case.
* gdb.python/py-value-cc.exp: Add new tests to test usage of
gdb.Field objects as subscripts on gdb.Value objects.
doc/
* gdb.texinfo (Values From Inferior): Add a note about using
gdb.Field objects as subscripts on gdb.Value objects.
(Types In Python): Add description about the new attribute
"parent_type" of gdb.Field objects.
I have a case that could use an exception for "unsupported feature".
I found UNSUPPORTED_ERROR, but looking deeper, I think as is, reusing
it for other things would be fragile. E.g., if the Python script
sourced by source_script_from_stream triggers any other missing
functionality that would result in UNSUPPORTED_ERROR being propagated
out to source_script_from_stream, that would confuse the error for
Python not being built into GDB.
This patch thus redoes things a little. Instead of using an exception
for the "No Python" scenario, check whether Python is configured in
before actually trying to source the file. It adds a new function
instead of using #ifdef HAVE_PYTHON directly, as that is better at
avoiding bitrot, as both Python and !Python paths are visible to the
compiler this way.
Tested on Fedora 17, with and without Python.
gdb/
2013-12-12 Pedro Alves <palves@redhat.com>
* cli/cli-cmds.c (source_script_from_stream) Use have_python
instead of catching UNSUPPORTED_ERROR.
* exceptions.h (UNSUPPORTED_ERROR): Delete.
* python/python.c (source_python_script) [!HAVE_PYTHON]: Internal
error if called.
* python/python.h (have_python): New static inline function.
This patch sanitizes the access to gdbarch made by various functions of
the SDT probe API. Before this patch, gdbarch was being accessed via
the probe's objfile; however, this proved to cause a bug on 32-bit ARM
targets because during the parsing of the probe's arguments the code
needed to access some pseudo-registers of the architecture, and this
information is not fully correct on the objfile's gdbarch.
Basically, the approach taken was to instead pass the current/selected
frame to the parsing and evaluation functions, so that they can extract
the gdbarch directly from the frame. It solved the ARM bug reported
above, and also contributed to make the API cleaner.
Tested on x86_64 and 32-bit ARM.
2013-12-11 Sergio Durigan Junior <sergiodj@redhat.com>
* break-catch-throw.c (fetch_probe_arguments): Pass selected frame
to get_probe_argument_count and evaluate_probe_argument.
* probe.c (get_probe_argument_count): Adjust declaration to accept
frame. Pass frame to probe_ops's get_probe_argument_count.
(evaluate_probe_argument): Likewise, for evaluate_probe_argument.
(probe_safe_evaluate_at_pc): Pass frame to
get_probe_argument_count and evaluate_probe_argument.
* probe.h (struct probe_ops) <get_probe_argument_count,
evaluate_probe_argument>: Adjust declarations to accept frame.
(get_probe_argument_count, evaluate_probe_argument): Likewise.
* solib-svr4.c (solib_event_probe_action): Get current frame.
Pass it to get_probe_argument_count.
(svr4_handle_solib_event): Get current frame. Pass it to
get_probe_argument_count and evaluate_probe_argument.
* stap-probe.c (stap_parse_probe_arguments): Adjust declaration to
accept gdbarch. Do not obtain it from the probe's objfile.
(stap_get_probe_argument_count): Adjust declaration to accept
frame. Obtain gdbarch from the frame. Call generic
can_evaluate_probe_arguments. Pass gdbarch to
stap_parse_probe_arguments.
(stap_get_arg): Adjust declaration to accept gdbarch. Pass it to
stap_parse_probe_arguments.
(stap_evaluate_probe_argument): Adjust declaration to accept
frame. Obtain gdbarch from the frame. Pass gdbarch to
stap_get_arg.
(stap_compile_to_ax): Pass agent_expr's gdbarch to stap_get_arg.
(compute_probe_arg): Obtain gdbarch from frame. Pass frame to
get_probe_argument_count and evaluate_probe_argument.
* c-lang.c (c_get_string): Ignore the declared size of the object
if a specific length is requested.
testsuite/
* gdb.python/py-value.c: #include stdlib.h, string.h.
(str): New struct.
(main): New local xstr.
* gdb.python/py-value.exp (test_value_in_inferior): Add test to
fetch a value as a string with a length beyond the declared length
of the array.
GDB is able to cache memory accesses requested in target_read_code,
so target_read_code is more efficient than general target_read_memory.
This patch uses target_read_code and its variants to read target
memory in the functions related to i386_skip_prologue. It improves
the performance when doing 'b foo' (foo is a function) in remote
debugging.
Nowadays, when we set a breakpoint on function f1, GDB will fetch the
code in f1 to determine the start of the function body (say skip the
prologue), it requests read from target many times. With this patch
applied, the number of RSP 'm' packets are reduced.
gdb:
2013-12-10 Yao Qi <yao@codesourcery.com>
* corefile.c (read_code): New function.
(read_code_integer): New function.
(read_code_unsigned_integer): New function.
* gdbcore.h (read_code): Declare.
(read_code_integer): Declare.
(read_code_unsigned_integer): Declare.
* i386-tdep.c (i386_follow_jump): Call target_read_code instead
of target_read_memory. Call read_code_unsigned_integer instead
of read_memory_unsigned_integer.
(i386_analyze_struct_return): Likewise.
(i386_skip_probe): Likewise.
(i386_analyze_stack_align): Likewise.
(i386_match_pattern): Likewise.
(i386_skip_noop): Likewise.
(i386_analyze_frame_setup): Likewise.
(i386_analyze_register_saves): Likewise.
(i386_skip_prologue): Likewise.
(i386_skip_main_prologue): Likewise.
(i386_frame_cache_1): Likewise.
This helps with the following issue: Given an Ada program defining
a global variable:
package Pck is
Watch : Integer := 1974;
end Pck;
When printing the address of this variable, GDB also tries to print
the associated symbol name:
(gdb) p watch'address
$1 = (access integer) 0x6139d8 <pck__watch>
^^
||
The problem is that GDB prints the variable's linkage name, instead
of its natural name. This is because the language of the associated
minimal symbol never really gets set.
This patch adds handling for Ada symbols in symbol_find_demangled_name.
After this patch, we now get:
(gdb) p watch'address
$1 = (access integer) 0x6139d8 <pck.watch>
^
|
gdb/ChangeLog:
* symtab.c (symbol_find_demangled_name): Add handling of
Ada symbols.
gdb/testsuite/ChangeLog:
* gdb.ada/int_deref.exp: Add test verifying that we print
the decoded symbol name when printing the address of Ada
symbols.
This adds "exec-run-start-option" in the output of the -list-features
commands, allowing front-ends to easily determine whether -exec-run
supports the --start option.
gdb/ChangeLog:
* mi/mi-main.c (mi_cmd_list_features): add "exec-run-start-option".
* NEWS: Expand the entry documenting the new -exec-run --start
option to mention the corresponding new entry in the output of
"-list-features".
gdb/doc/ChangeLog:
* gdb.texinfo (GDB/MI Miscellaneous Commands): Document the new
"exec-run-start-option" entry in the output of the "-list-features"
command.
gdb/testsuite/ChangeLog:
* gdb.mi/mi-start.exp: Add test verifying that -list-features
contains "exec-run-start-option".
We observed on Windows 2012 that we were unable to unwind past
exception handlers. For instance, with any Ada program raising
an exception that does not get handled:
% gnatmake -g a -bargs -shared
% gdb a
(gdb) start
(gdb) catch exception unhandled
Catchpoint 2: unhandled Ada exceptions
(gdb) c
Catchpoint 2, unhandled CONSTRAINT_ERROR at <__gnat_unhandled_exception> (
e=0x645ff820 <constraint_error>) at s-excdeb.adb:53
53 s-excdeb.adb: No such file or directory.
At this point, we can already see that something went wrong, since
the frame selected by the debugger corresponds to a runtime function
rather than the function in the user code that caused the exception
to be raised (in our case procedure A).
This is further confirmed by the fact that we are unable to unwind
all the way to procedure A:
(gdb) bt
#0 <__gnat_unhandled_exception> (e=0x645ff820 <constraint_error>)
at s-excdeb.adb:53
#1 0x000000006444e9a3 in <__gnat_notify_unhandled_exception> (excep=0x284d2
+0)
at a-exextr.adb:144
#2 0x00000000645f106a in __gnat_personality_imp ()
from C:\[...]\libgnat-7.3.dll
#3 0x000000006144d1b7 in _GCC_specific_handler (ms_exc=0x242fab0,
this_frame=0x242fe60, ms_orig_context=0x242f5c0, ms_disp=0x242ef70,
gcc_per=0x645f0960 <__gnat_personality_imp>)
at ../../../src/libgcc/unwind-seh.c:289
#4 0x00000000645f1211 in __gnat_personality_seh0 ()
from C:\[...]\libgnat-7.3.dll
#5 0x000007fad3879f4d in ?? ()
Backtrace stopped: previous frame inner to this frame (corrupt stack?)
It turns out that the unwinder has been doing its job flawlessly
up until frame #5. The address in frame #5 is correct, but GDB
is not able to associate it with any symbol or unwind record.
And this is because this address is inside ntdll.dll, and when
we received the LOAD_DLL_DEBUG_EVENT for that DLL, the system
was not able to tell us the name of the library, thus causing us
to silently ignoring the event. Because GDB does not know about
ntdll.dll, it is unable to access the unwind information from it.
And because the function at that address does not use a frame
pointer, the unwinding becomes impossible.
This patch helps recovering ntdll.dll at the end of the "run/attach"
phase, simply by trying to locate that specific DLL again.
In terms of our medium to long term planning, it seems to me that
we should be able to simplify the code by ignoring LOAD_DLL_DEBUG_EVENT
during the startup phase, and modify windows_ensure_ntdll_loaded
to then detect and report all shared libraries after we've finished
inferior creation. But for a change just before 7.7 branch creation,
I thought it was safest to just handle ntdll.dll specifically. This
is less intrusive, and ntdll is the only DLL affected by the problem
I know so far.
gdb/ChangeLog:
* windows-nat.c (handle_load_dll): Add comments.
(windows_ensure_ntdll_loaded): New function.
(do_initial_windows_stuff): Use windows_ensure_ntdll_loaded.
Add FIXME comment.
Hi,
I see such warning below on one compiler I am using.
cc1: warnings being treated as errors
../../workspace/gdb/stack.c: In function 'frame_info':
../../workspace/gdb/stack.c:1519:20: error: 'caller_pc' may be used uninitialized in this function
Go through the gdb-patches archives and find the "canonical" way to
fix this warning is to initialize the variable.
gdb:
2013-12-08 Yao Qi <yao@codesourcery.com>
* stack.c (frame_info): Initialize variable caller_pc.
Doing "info frame" in the outermost frame, when that was indicated by
the next frame saying the unwound PC is undefined/not saved, results
in error and incomplete output:
(gdb) bt
#0 thread_function0 (arg=0x0) at threads.c:63
#1 0x00000034cf407d14 in start_thread (arg=0x7ffff7fcb700) at pthread_create.c:309
#2 0x000000323d4f168d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:115
(gdb) frame 2
#2 0x000000323d4f168d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:115
115 call *%rax
(gdb) info frame
Stack level 2, frame at 0x0:
rip = 0x323d4f168d in clone (../sysdeps/unix/sysv/linux/x86_64/clone.S:115); saved rip Register 16 was not saved
(gdb)
Not saved register values are treated as optimized out values
internally throughout. stack.c:frame_info is handing unvailable
values, but not optimized out ones. The patch deletes the
frame_unwind_caller_pc_if_available wrapper function and instead lets
errors propagate to frame_info (it's only user).
As frame_unwind_pc now needs to be able to handle and cache two
different error scenarios, the prev_pc.p variable is replaced with an
enumeration.
(FWIW, I looked into making gdbarch_unwind_pc or a variant return
struct value's instead, but it results in lots of boxing and unboxing
for no real gain -- e.g., the mips and arm implementations need to do
computation on the unboxed PC value. Might as well throw an error on
first attempt to get at invalid contents.)
After the patch, we get:
(gdb) info frame
Stack level 2, frame at 0x0:
rip = 0x323d4f168d in clone (../sysdeps/unix/sysv/linux/x86_64/clone.S:115); saved rip = <not saved>
Outermost frame: outermost
caller of frame at 0x7ffff7fcafc0
source language asm.
Arglist at 0x7ffff7fcafb8, args:
Locals at 0x7ffff7fcafb8, Previous frame's sp is 0x7ffff7fcafc8
(gdb)
A new test is added. It's based off dw2-reg-undefined.exp, and tweaked to
mark the return address (rip) of "stop_frame" as undefined.
Tested on x86_64 Fedora 17.
gdb/
2013-12-06 Pedro Alves <palves@redhat.com>
* frame.c (enum cached_copy_status): New enum.
(struct frame_info) <prev_pc.p>: Change type to enum
cached_copy_status.
(fprint_frame): Handle not saved and unavailable prev_pc values.
(frame_unwind_pc_if_available): Delete and merge contents into ...
(frame_unwind_pc): ... here. Handle OPTIMIZED_OUT_ERROR. Adjust
to use enum cached_copy_status.
(frame_unwind_caller_pc_if_available): Delete.
(create_new_frame): Adjust.
* frame.h (frame_unwind_caller_pc_if_available): Delete
declaration.
* stack.c (frame_info): Use frame_unwind_caller_pc instead of
frame_unwind_caller_pc_if_available, and handle
NOT_AVAILABLE_ERROR and OPTIMIZED_OUT_ERROR errors.
* valprint.c (val_print_optimized_out): Use val_print_not_saved.
(val_print_not_saved): New function.
* valprint.h (val_print_not_saved): Declare.
gdb/testsuite/
2013-12-06 Pedro Alves <palves@redhat.com>
* gdb.dwarf2/dw2-undefined-ret-addr.S: New file.
* gdb.dwarf2/dw2-undefined-ret-addr.c: New file.
* gdb.dwarf2/dw2-undefined-ret-addr.exp: New file.
In order to catch <optimized out> errors like we catch <unavailable>
errors, this adds a new OPTIMIZED_OUT_ERROR error code, and throws it
in various places.
gdb/ChangeLog
2013-12-06 Andrew Burgess <aburgess@broadcom.com>
Pedro Alves <palves@redhat.com>
* exceptions.h (errors): Add OPTIMIZED_OUT_ERROR.
* dwarf2loc.c (write_pieced_value): Throw OPTIMIZED_OUT_ERROR.
* frame.c (frame_unwind_register): Throw OPTIMIZED_OUT_ERROR.
* spu-tdep.c (spu_software_single_step): Throw
OPTIMIZED_OUT_ERROR.
* valops.c (value_assign): Throw OPTIMIZED_OUT_ERROR.
The introductory comment to free_objfile is obsolete.
This patch fixes it by removing all the obsolete bits.
2013-12-06 Tom Tromey <tromey@redhat.com>
* objfiles.c (free_objfile): Update comment.
I happened to notice that nothing uses objfile_to_front.
This patch removes it.
2013-12-06 Tom Tromey <tromey@redhat.com>
* objfiles.h (objfile_to_front): Remove.
* objfiles.c (objfile_to_front): Remove.
This removes an unnecessary declaration from minsyms.c.
2013-12-06 Tom Tromey <tromey@redhat.com>
* minsyms.c (get_symbol_leading_char): Remove unnecessary
declaration.
This improves the packing of struct partial_symtab. I noticed with
pahole that were were a couple of holes. This consolidates the holes
without, I think, affecting readability -- it just moves the "user"
field a bit earlier in the struct. This change saves a small amount
of memory.
2013-12-06 Tom Tromey <tromey@redhat.com>
* psympriv.h (struct partial_symtab) <user>: Move earlier.
This fixes a couple of old "32x64" FIXME comments by using paddress
with current_gdbarch rather than hex_string and a cast to long.
2013-12-06 Tom Tromey <tromey@redhat.com>
* cli/cli-cmds.c (edit_command): Use paddress, not hex_string.
(list_command): Likewise.
This puts the psymtab filename in the filename bcache.
This saves a small amount of memory.
2013-12-06 Tom Tromey <tromey@redhat.com>
* psymtab.c (allocate_psymtab): Put the filename in the filename
bcache.
This makes symtab::dirname const and updates one spot to avoid an
intermediate constless result.
2013-12-06 Tom Tromey <tromey@redhat.com>
* buildsym.c (end_symtab_from_static_block): Use obstack_copy0.
* symtab.h (struct symtab) <dirname>: Now const.
This makes symtab::filename const and removes a newly unnecessary
cast.
2013-12-06 Tom Tromey <tromey@redhat.com>
* symfile.c (allocate_symtab): Remove cast.
* symtab.h (struct symtab) <filename>: Now const.
While looking into the probe API, it seemed to me that there were a
number of methods in sym_probe_fns that were not needed. This patch
removes them.
Specifically, it seems to me that sym_probe_fns ought to be concerned
with the API for constructing the probes. Any method relating to some
aspect of an individual probe can be handled via the probe's own
vtable. That is, the double indirection here doesn't seem useful --
it certainly isn't in fact used, but also I couldn't think of a
potential use.
2013-12-06 Tom Tromey <tromey@redhat.com>
* break-catch-throw.c (fetch_probe_arguments): Use
get_probe_argument_count and evaluate_probe_argument.
* elfread.c (elf_get_probe_argument_count)
(elf_can_evaluate_probe_arguments, elf_evaluate_probe_argument)
(elf_compile_to_ax): Remove.
(elf_probe_fns): Update.
* probe.c (get_probe_argument_count, can_evaluate_probe_arguments)
(evaluate_probe_argument): Call method on probe, not via sym
functions.
* stap-probe.c (compute_probe_arg): Use get_probe_argument_count,
evaluate_probe_argument.
(compile_probe_arg): Use get_probe_argument_count. Call method on
probe, not via sym functions.
* symfile-debug.c (debug_sym_get_probe_argument_count)
(debug_can_evaluate_probe_arguments)
(debug_sym_evaluate_probe_argument, debug_sym_compile_to_ax):
Remove.
(debug_sym_probe_fns): Remove.
* symfile.h (struct sym_probe_fns) <sym_get_probe_argument_count,
can_evaluate_probe_arguments, sym_evaluate_probe_argument,
sym_compile_to_ax>: Remove fields.
* p-exp.y (exp : field_exp name): Do not call mark_struct_expression.
(exp : field_exp name COMPLETE): New rule.
(exp : SIZEOF): Set correct current_type.
(last_was_structop): Remove static variable.
(yylex): Remove saw_structop local variable.
Adapt code to removal of variables above.
With a simple Ada program where I have 3 functions, one just calling
the next, the backtrace is currently broken when GDB is compiled
at -O2:
#0 hello.first () at hello.adb:5
#1 0x0000000100001475 in hello.second () at hello.adb:10
Backtrace stopped: previous frame inner to this frame (corrupt stack?)
It turns out that a recent patch deleted the assignment of variable
this_id, making it an unitialized variable:
* frame-unwind.c (default_frame_unwind_stop_reason): Return
UNWIND_OUTERMOST if the frame's ID is outer_frame_id.
* frame.c (get_prev_frame_1): Remove outer_frame_id check.
The hunk in question starts with:
- /* Check that this frame is not the outermost. If it is, don't try
- to unwind to the prev frame. */
- this_id = get_frame_id (this_frame);
- if (frame_id_eq (this_id, outer_frame_id))
(the code was removed as redundant - but removing the assignment
was in fact not intentional).
There is no other code in this function that sets the variable.
Instead of re-adding the statement in the lone section where it is
actually used, I inlined it, and then got rid of the variable
altogether. This way, and until we start needing this frame ID
in another location within that function, we dont' have to worry
about the variable's validity/lifetime.
gdb/ChangeLog:
* frame.c (get_prev_frame_1): Delete variable "this_id".
Replace its use by a call to get_frame_id.
We've observed in Windows 2012 that ntdll.dll contains some unwind
records with the version field set to 2. This patch adjusts the
decoder to accept records flagged with this version as well.
Version 2 appears to still be largely undocumented at this stage.
However, apart from a mysterious opcode 6, everything else still
seems to remain the same. So this patch also changes the decoder
to ignore those opcodes; before this change, the debugger would
silently stop the decoding, and let the frame unwinder make do
with what it the decoder managed to decode up to that point.
It's unclear at this point what we're losing by not being able to
decode that opcode. But the information does not appear to be critical,
at least as far as call unwinding is concerned.
gdb/ChangeLog:
(from Tristan Gingold <gingold@adacore.com>)
(from Joel Brobecker <brobecker@adacore.com>)
* amd64-windows-tdep.c (amd64_windows_frame_decode_insns):
Accept version 2. Ignore operations using opcode 6.
Consider the following code:
type Ptr is access all Integer;
IP : Ptr := new Integer'(123);
IP is the Ada exception of a pointer to an integer. To dereference
the pointer and get its value, the user uses the reserved word "all"
as follow:
(gdb) p ip.all
$1 = 123
Ada being a case-insensitive language, the casing should not matter.
Unfortunately, for the reserved word "all", things don't work. For
instance:
(gdb) p ip.ALL
Type integer is not a structure or union type
This patch fixes the problem.
gdb/ChangeLog:
* ada-lex.l (find_dot_all): Use strncasecmp instead of strncmp.
gdb/testsuite/ChangeLog:
* gdb.ada/dot_all: New testcase.
With a program raising an exception, trying to debug that program
in GDB/MI mode can yield a crash:
% gdb -i=mi foo
(gdb)
-catch-exception -e "Program_Error"
^done,bkptno="2",bkpt={number="2",type="breakpoint",[...]
(gdb)
-exec-continue
^running
*running,thread-id="all"
(gdb)
=library-loaded,id=[...]
&"warning: failed to reevaluate internal exception condition for catchpoint 2: Error in expression, near `'.\n"
zsh: 22956 bus error (core dumped) gdb -q -i=mi foo
The problem is triggered by a problem in the compiler which causes
EXP in the following TRY_CATCH block to change unexpectedly when
parse_exp_1 throws an error :
| TRY_CATCH (e, RETURN_MASK_ERROR)
| {
| exp = parse_exp_1 (&s, bl->address,
| block_for_pc (bl->address), 0);
| }
In ada-lang.c:create_excep_cond_exprs, EXP is initialized to NULL,
and is expected to remain NULL if parse_exp_1 throws. Instead,
its value gets changed to something invalid. This later crashes
the debugger, when trying to evaluate the bogus expression.
This patch works around the issue by simply forcing EXP back to NULL
when an exception was thrown. A comment explaining why, and the sort
of timeline we're looking at for a fix, is also added.
gdb/ChangeLog:
* ada-lang.c (create_excep_cond_exprs): Force EXP to NULL
when parse_exp_1 threw an error. Add comment.
This patch extends a bit the news entry we added which documents
general support of the --language option, to add a small reference
to the associated entry which was also added to the "-list-features"
command output.
gdb/ChangeLog:
* NEWS: Mention "-list-features" in the entry documenting
the support for the "--language" option.
Now that the -info-gdb-mi-command is available, there is no need for
this entry. The entry and associated new commands were added recently
enough that no front-end out there should be depending on it yet.
gdb/ChangeLog:
* mi/mi-main.c (mi_cmd_list_features): Remove "ada-exceptions".
gdb/doc/ChangeLog:
* gdb.texinfo (GDB/MI Miscellaneous Commands): Remove the
documentation of the "ada-exceptions" entry.
... when trying to execute an undefined GDB/MI command. When trying
to execute a GDB/MI command which does not exist, the current error
result record looks like this:
-unsupported
^error,msg="Undefined MI command: unsupported"
The only indication that the command does not exist is the error
message. It would be a little fragile for a consumer to rely solely
on the contents of the error message in order to determine whether
a command exists or not.
This patch improves the situation by adding concept of error
code, starting with one well-defined error code ("undefined-command")
identifying errors due to a non-existant command. Here is the new
output:
-unsupported
^error,msg="Undefined MI command: unsupported",code="undefined-command"
This error code is only displayed when the corresponding error
condition is met. Otherwise, the error record remains unchanged.
For instance:
-symbol-list-lines foo.adb
^error,msg="-symbol-list-lines: Unknown source file name."
For frontends to be able to know whether they can rely on this
variable, a new entry "undefined-command-error-code" has been
added to the "-list-features" command. Another option would be
to always generate an error="..." variable (for the default case,
we could decide for instance that the error code is the empty string).
But it seems more efficient to provide that info in "-list-features"
and then only add the error code when meaningful.
gdb/ChangeLog:
(from Pedro Alves <palves@redhat.com>)
(from Joel Brobecker <brobecker@adacore.com>)
* exceptions.h (enum_errors) <UNDEFINED_COMMAND_ERROR>: New enum.
* mi/mi-parse.c (mi_parse): Throw UNDEFINED_COMMAND_ERROR instead
of a regular error when the GDB/MI command does not exist.
* mi/mi-main.c (mi_cmd_list_features): Add
"undefined-command-error-code".
(mi_print_exception): Print an "undefined-command"
error code if EXCEPTION.ERROR is UNDEFINED_COMMAND_ERROR.
* NEWS: Add entry documenting the new "code" variable in
"^error" result records.
gdb/doc/ChangeLog:
* gdb.texinfo (GDB/MI Result Records): Fix the syntax of the
"^error" result record concerning the error message. Document
the error code that may also be part of that result record.
(GDB/MI Miscellaneous Commands): Document the
"undefined-command-error-code" element in the output of
the "-list-features" GDB/MI command.
gdb/testsuite/ChangeLog:
* gdb.mi/mi-undefined-cmd.exp: New testcase.
This patch adds a new GDB/MI command meant for graphical frontends
trying to determine whether a given GDB/MI command exists or not.
Examples:
-info-gdb-mi-command unsupported-command
^done,command={exists="false"}
(gdb)
-info-gdb-mi-command symbol-list-lines
^done,command={exists="true"}
(gdb)
At the moment, this is the only piece of information that this
command returns.
Eventually, and if needed, we can extend it to provide
command-specific pieces of information, such as updates to
the command's syntax since inception. This could become,
for instance:
-info-gdb-mi-command symbol-list-lines
^done,command={exists="true",features=[]}
(gdb)
-info-gdb-mi-command catch-assert
^done,command={exists="true",features=["conditions"]}
In the first case, it would mean that no extra features,
while in the second, it announces that the -catch-assert
command in this version of the debugger supports a feature
called "condition" - exact semantics to be documented with
combined with the rest of the queried command's documentation.
But for now, we start small, and only worry about existance.
And to bootstrap the process, I have added an entry in the
output of the -list-features command as well ("info-gdb-mi-command"),
allowing the graphical frontends to go through the following process:
1. Send -list-features, collect info from there as before;
2. Check if the output contains "info-gdb-mi-command".
If it does, then support for various commands can be
queried though -info-gdb-mi-command. Newer commands
will be expected to always be checked via this new
-info-gdb-mi-command.
gdb/ChangeLog:
* mi/mi-cmds.h (mi_cmd_info_gdb_mi_command): Declare.
* mi/mi-cmd-info.c (mi_cmd_info_gdb_mi_command): New function.
* mi/mi-cmds.c (mi_cmds): Add -info-gdb-mi-command command.
* mi/mi-main.c (mi_cmd_list_features): Add "info-gdb-mi-command"
field to output of "-list-features".
* NEWS: Add entry for new -info-gdb-mi-command.
gdb/doc/ChangeLog:
* gdb.texinfo (GDB/MI Miscellaneous Commands): Document
the new -info-gdb-mi-command GDB/MI command. Document
the meaning of "-info-gdb-mi-command" in the output of
-list-features.
gdb/testsuite/ChangeLog:
* gdb.mi/mi-i-cmd.exp: New file.
gdb/
2013-12-02 Doug Evans <dje@google.com>
Jan Kratochvil <jan.kratochvil@redhat.com>
* objfiles.c (allocate_objfile): Save original_name as an absolute
path.
* objfiles.h (struct objfile): Expand comment on original_name.
* source.c (openp): Call gdb_abspath.
* utils.c (gdb_abspath): New function.
* utils.h (gdb_abspath): Declare.
gdb/testsuite/
2013-12-02 Doug Evans <dje@google.com>
* gdb.dwarf/dwp-symlink.c: Fake out gdb to not load debug info
at start.
* gdb.dwarf/dwp-symlink.exp: Test trying to load dwp when the binary
has been specified with a relative path and we have chdir'd before
accessing the debug info.
Confirmed that cross building a mingw gdb still works, and also made
sure it was gnulib's sys/stat.h that was defining the values, by
hacking the header with #errors where the macros are defined.
gdb/
2013-12-02 Pedro Alves <palves@redhat.com>
* ctf.c (ctf_start): Use S_IRGRP, S_IXGRP, S_IXOTH
unconditionally.
Remote servers may cut the connection abruptly since they are not
required to reply to a 'k' (Kill) packet sent from GDB.
This patch addresses any issues arising from such scenario, which
leads to a GDB internal error due to an attempt to pop the target more
than once. With the patch, this failure is handled gracefully.
Here's the GDB backtrace Maciej got running the testsuite against
QEMU. Full paths edited out for brevity.
#0 0x55573430 in __kernel_vsyscall ()
#1 0x557a2951 in raise () from /lib32/libc.so.6
#2 0x557a5d82 in abort () from /lib32/libc.so.6
#3 0x0826e2e4 in dump_core ()
at .../gdb/utils.c:635
#4 0x0826e5b6 in internal_vproblem (problem=0x85200c0,
file=0x8416be8 ".../gdb/target.c", line=2861,
fmt=0x84174ac "could not find a target to follow mourn inferior",
ap=0xffa4796c "\f")
at .../gdb/utils.c:804
#5 0x0826e5fb in internal_verror (
file=0x8416be8 ".../gdb/target.c", line=2861,
fmt=0x84174ac "could not find a target to follow mourn inferior",
ap=0xffa4796c "\f")
at .../gdb/utils.c:820
#6 0x0826e633 in internal_error (
file=0x8416be8 ".../gdb/target.c", line=2861,
string=0x84174ac "could not find a target to follow mourn inferior")
at .../gdb/utils.c:830
#7 0x081b4ad0 in target_mourn_inferior ()
at .../gdb/target.c:2861
#8 0x08082283 in remote_kill (ops=0x85245e0)
at .../gdb/remote.c:7840
#9 0x081b06d1 in target_kill ()
at .../gdb/target.c:486
#10 0x081b42f6 in dispose_inferior (inf=0xa501c60, args=0x0)
at .../gdb/target.c:2570
#11 0x08290cfc in iterate_over_inferiors (
callback=0x81b42af <dispose_inferior>, data=0x0)
at .../gdb/inferior.c:396
#12 0x081b435a in target_preopen (from_tty=1)
at .../gdb/target.c:2591
#13 0x0807c2c6 in remote_open_1 (name=0xa5538b6 "localhost:1237", from_tty=1,
target=0x85245e0, extended_p=0)
at .../gdb/remote.c:4292
#14 0x0807b7a8 in remote_open (name=0xa5538b6 "localhost:1237", from_tty=1)
at .../gdb/remote.c:3655
#15 0x080a23d4 in do_cfunc (c=0xa464f30, args=0xa5538b6 "localhost:1237",
from_tty=1)
at .../gdb/cli/cli-decode.c:107
#16 0x080a4c3b in cmd_func (cmd=0xa464f30, args=0xa5538b6 "localhost:1237",
from_tty=1)
at .../gdb/cli/cli-decode.c:1882
#17 0x0826bebf in execute_command (p=0xa5538c3 "7", from_tty=1)
at .../gdb/top.c:467
#18 0x08193f2d in command_handler (command=0xa5538a8 "")
at .../gdb/event-top.c:435
#19 0x08194463 in command_line_handler (
rl=0xa778198 "target remote localhost:1237")
at .../gdb/event-top.c:633
#20 0x082ba92b in rl_callback_read_char ()
at .../readline/callback.c:220
#21 0x08193adf in rl_callback_read_char_wrapper (client_data=0x0)
at .../gdb/event-top.c:164
#22 0x08193e57 in stdin_event_handler (error=0, client_data=0x0)
at .../gdb/event-top.c:375
#23 0x08192f29 in handle_file_event (data=...)
at .../gdb/event-loop.c:768
#24 0x0819266a in process_event ()
at .../gdb/event-loop.c:342
#25 0x08192708 in gdb_do_one_event ()
at .../gdb/event-loop.c:394
#26 0x08192781 in start_event_loop ()
at .../gdb/event-loop.c:431
#27 0x08193b08 in cli_command_loop (data=0x0)
at .../gdb/event-top.c:179
#28 0x0818bc26 in current_interp_command_loop ()
at .../gdb/interps.c:327
#29 0x0818c4e5 in captured_command_loop (data=0x0)
at .../gdb/main.c:267
#30 0x0818a37f in catch_errors (func=0x818c4d0 <captured_command_loop>,
func_args=0x0, errstring=0x8402108 "", mask=RETURN_MASK_ALL)
at .../gdb/exceptions.c:524
#31 0x0818d736 in captured_main (data=0xffa47f10)
at .../gdb/main.c:1067
#32 0x0818a37f in catch_errors (func=0x818c723 <captured_main>,
func_args=0xffa47f10, errstring=0x8402108 "", mask=RETURN_MASK_ALL)
at .../gdb/exceptions.c:524
#33 0x0818d76c in gdb_main (args=0xffa47f10)
at .../gdb/main.c:1076
#34 0x0804dd1b in main (argc=5, argv=0xffa47fd4)
at .../gdb/gdb.c:34
The corresponding gdb.log excerpt:
(gdb) PASS: gdb.base/bitfields.exp: bitfield uniqueness (u9)
cont
Continuing.
Breakpoint 1, break1 () at .../gdb/testsuite/gdb.base/bitfields.c:44
44 }
(gdb) PASS: gdb.base/bitfields.exp: continuing to break1 #9
print flags
$10 = {uc = 0 '\000', s1 = 0, u1 = 0, s2 = 0, u2 = 0, s3 = 0, u3 = 0, s9 = 0, u9 = 0, sc = 1 '\001'}
(gdb) PASS: gdb.base/bitfields.exp: bitfield uniqueness (sc)
delete breakpoints
Delete all breakpoints? (y or n) y
(gdb) info breakpoints
No breakpoints or watchpoints.
(gdb) delete breakpoints
(gdb) info breakpoints
No breakpoints or watchpoints.
(gdb) break break2
Breakpoint 2 at 0x85f8: file .../gdb/testsuite/gdb.base/bitfields.c, line 48.
(gdb) entering gdb_reload
target remote localhost:1235
A program is being debugged already. Kill it? (y or n) y
Remote connection closed
.../gdb/target.c:2861: internal-error: could not find a target to follow mourn inferior
A problem internal to GDB has been detected,
further debugging may prove unreliable.
Quit this debugging session? (y or n) ^Ccontinue
Please answer y or n.
.../gdb/target.c:2861: internal-error: could not find a target to follow mourn inferior
A problem internal to GDB has been detected,
further debugging may prove unreliable.
Quit this debugging session? (y or n) Resyncing due to internal error.
n
.../gdb/target.c:2861: internal-error: could not find a target to follow mourn inferior
A problem internal to GDB has been detected,
further debugging may prove unreliable.
Create a core file of GDB? (y or n) y
Command aborted.
(gdb) print/x flags
$11 = {uc = 0x0, s1 = 0x0, u1 = 0x0, s2 = 0x0, u2 = 0x0, s3 = 0x0, u3 = 0x0, s9 = 0x0, u9 = 0x0, sc = 0x0}
(gdb) FAIL: gdb.base/bitfields.exp: bitfield containment #1
cont
The program is not being run.
(gdb) FAIL: gdb.base/bitfields.exp: continuing to break2 (the program is no longer running)
print/x flags
$12 = {uc = 0x0, s1 = 0x0, u1 = 0x0, s2 = 0x0, u2 = 0x0, s3 = 0x0, u3 = 0x0, s9 = 0x0, u9 = 0x0, sc = 0x0}
(gdb) FAIL: gdb.base/bitfields.exp: bitfield containment #2
delete breakpoints
Delete all breakpoints? (y or n) y
(gdb) info breakpoints
No breakpoints or watchpoints.
(gdb) delete breakpoints
(gdb) info breakpoints
No breakpoints or watchpoints.
(gdb) break break3
Breakpoint 3 at 0x8604: file .../gdb/testsuite/gdb.base/bitfields.c, line 52.
(gdb) entering gdb_reload
target remote localhost:1236
Remote debugging using localhost:1236
Reading symbols from .../lib/ld-linux.so.3...done.
Loaded symbols for .../lib/ld-linux.so.3
0x41001b80 in _start () from .../lib/ld-linux.so.3
(gdb) continue
Continuing.
Breakpoint 3, break3 () at .../gdb/testsuite/gdb.base/bitfields.c:52
52 }
(gdb) print flags
$13 = {uc = 0 '\000', s1 = 0, u1 = 1, s2 = 0, u2 = 3, s3 = 0, u3 = 7, s9 = 0, u9 = 511, sc = 0 '\000'}
(gdb) PASS: gdb.base/bitfields.exp: unsigned bitfield ranges
gdb/
2013-12-02 Pedro Alves <pedro@codesourcery.com>
Maciej W. Rozycki <macro@codesourcery.com>
* remote.c (putpkt_for_catch_errors): Remove function.
(remote_kill): Handle TARGET_CLOSE_ERROR from the kill packet
gracefully.
In remote-notif.c:handle_notification, we have a loop,
for (i = 0; i < ARRAY_SIZE (notifs); i++)
{
nc = notifs[i];
if (strncmp (buf, nc->name, strlen (nc->name)) == 0
&& buf[strlen (nc->name)] == ':')
break;
}
/* We ignore notifications we don't recognize, for compatibility
with newer stubs. */
if (nc == NULL)
return;
If the notification is not in the list 'notifs', the last entry is
used, which is wrong. It should be NULL. This patch fixes it.
gdb:
2013-12-02 Pedro Alves <palves@redhat.com>
PR remote/15974
* remote-notif.c (handle_notification): Return early if no
notification is found.
Not all systems supporting getrlimit also support RLIMIT_NOFILE
(Eg. All LynxOS systems appear to be lacking support for this).
So check its existance before using it.
gdb/ChangeLog:
* common/filestuff.c (fdwalk): Add "defined(RLIMIT_NOFILE)"
preprocessor check.
Simplify handling of auto-loaded objfile scripts.
.debug_gdb_scripts was always intended to handle more than just python,
thus the rightful home for the code that processes it is not in py-foo.c.
This is just a cleanup to move the code to a better place.
This also simplifies the handling of the ${objfile}-${suffix} auto-loaded
scripts. There's no need for each of the the handlers to do is-safe-to-load
checking, or call maybe_add_script. Doing it in the caller removes the
duplication.
* auto-load.h (script_language): New members name, auto_load_enabled.
Add missing comments on struct members.
(auto_load_objfile_script): Delete.
* auto-load.c: #include "cli/cli-cmds.h".
(auto_load_gdb_scripts_enabled): New function.
(script_language_gdb): Update, add new members.
(source_gdb_script_for_objfile): Simplify, auto-load safe-checking
and call to maybe_add_script moved to caller.
(auto_load_objfile_script_1): Auto-load safe-checking and
call to maybe_add_script moved here.
(auto_load_objfile_script): Make static. Early exit if support for
scripting language hasn't been compiled in, or auto-loading has been
disabled.
(source_section_scripts): Argument "source_name" renamed to
"section_name". All uses updated. Replace uses of AUTO_SECTION_NAME
with section_name. Skip loading script if support for scripting
language hasn't been compiled in, or auto-loading has been disabled.
Call language->source_script_for_objfile instead of calling
source_python_script_for_objfile directly.
(load_auto_scripts_for_objfile): Update.
* python/py-auto-load.c: Delete #include "cli/cli-cmds.h".
(gdbpy_load_auto_script_for_objfile): Delete.
(auto_load_python_scripts_enabled): New function.
(script_language_python): Update, add new members.
(gdbpy_script_language_defn): New function.
* python/python.h (gdbpy_load_auto_scripts_for_objfile): Delete.
(gdbpy_script_language_defn): Declare.
* auto-load.c (AUTO_SECTION_NAME): Moved here and renamed from
py-auto-load.c, GDBPY_AUTO_SECTION_NAME.
(source_section_scripts): Moved here from py-auto-load.c.
(auto_load_section_scripts): Ditto.
* python/py-auto-load.c (GDBPY_AUTO_SECTION_NAME): Moved to
auto-load.c, renamed AUTO_SECTION_NAME.
(source_section_scripts, auto_load_section_scripts): Moved to
auto-load.c.
This commit removes the "#include gdb_string.h" from gdbarch.sh, fixing
a small nit caused by Tom's commit
0e9f083f4c.
Checked-in as obvious.
2013-11-29 Sergio Durigan Junior <sergiodj@redhat.com>
* gdbarch.sh: Remove include of "gdb_string.h", replace by
<string.h>.
Unfortunately, UNWIND_NULL_ID is exported to Python as
gdb.FRAME_UNWIND_NULL_ID so we can't really eliminate it.
(I'd assume scripts just check the result of Frame.unwind_stop_reason,
and compare it to gdb.FRAME_UNWIND_NO_REASON. That at most, they'll
pass the result of Frame.unwind_stop_reason to
gdb.frame_stop_reason_string. I'd prefer to just get rid of it, but
because we make an API promise, we get to keep this around for
compatibility, in case a script does refer to gdb.FRAME_UNWIND_NULL_ID
directly.)
gdb/
2013-11-29 Pedro Alves <palves@redhat.com>
* unwind_stop_reasons.def (UNWIND_NULL_ID): Update comment.
gdb/doc/
2013-11-29 Pedro Alves <palves@redhat.com>
* gdb.texinfo (Frames In Python) <gdb.FRAME_UNWIND_NULL_ID>:
Update comment.
The memory management of bp_location->target_info.conditions|tcommands
is currently a little fragile. If the target reports support for
target conditions or commands, and then target side breakpoint support
is disabled, or some error is thrown before remote_add_target_side_XXX
is called, we'll leak these lists. This patch makes us free these
lists when the locations are deleted, and also, just before recreating
the commands|conditions lists.
Tested on x86_64 Fedora 17, native and gdbserver.
gdb/
2013-11-29 Pedro Alves <palves@redhat.com>
* breakpoint.c (build_target_condition_list): Release previous
conditions.
(build_target_command_list): Release previous commands.
(bp_location_dtor): Release target conditions and commands.
* remote.c (remote_add_target_side_condition): Don't release
conditions.
(remote_add_target_side_commands): Don't release commands.
GDB on x86_64-linux is unable to disassemble on core-file target.
$ ./gdb ./testsuite/gdb.base/corefile
(gdb) core-file ./testsuite/gdb.base/corefile.core
(gdb) disassemble main
Dump of assembler code for function main:
0x0000000000400976 <+0>: Cannot access memory at address 0x400976
However, it works if we turn code-cache off.
(gdb) set code-cache off
(gdb) disassemble main,+4
Dump of assembler code from 0x400976 to 0x40097a:
0x0000000000400976 <main+0>: push %rbp
0x0000000000400977 <main+1>: mov %rsp,%rbp
End of assembler dump.
When code-cache is off, GDB will iterate target_ops from top to bottom
and call to_xfer_partial. When current_target is "core", it will call
to_xfer_partial of target "exec", which reads the contents for
disassemble. However, dcache uses TARGET_OBJECT_RAW_MEMORY to read,
but target_xfer_partial doesn't delegate requests to beneath for
TARGET_OBJECT_RAW_MEMORY.
This patch factors out the iteration from top to bottom to a new
function, raw_memory_xfer_partial, and use it for
TARGET_OBJECT_RAW_MEMORY.
Regression tested on x86_64-linux.
gdb:
2013-11-29 Yao Qi <yao@codesourcery.com>
Pedro Alves <palves@redhat.com>
* dcache.c (dcache_read_line): Use current_target.beneath
instead of ¤t_target.
* target.c (memory_xfer_partial_1): Factor code out to ...
(raw_memory_xfer_partial): ... it. New function.
(target_xfer_partial): Call raw_memory_xfer_partial if OBJECT
is TARGET_OBJECT_RAW_MEMORY.
* breakpoint.h (gdbpy_breakpoint_object): Renamed from
breakpoint_object. All uses updated.
* python/python-internal.h (gdbpy_breakpoint_object): Renamed from
breakpoint_object. All uses updated.
* python.c (*): All uses of breakpoint_object updated.
* python.h (*): All uses of breakpoint_object updated.
* python/py-breakpoint.c (*): All uses of breakpoint_object updated.
* python/py-finishbreakpoint.c (*): Ditto.
When printing an entirely optimized out structure/class/union, we
print a single <optimized out> instead of printing <optimized out> for
each field.
This patch makes an entirely unavailable structure/class/union be
likewise displayed with a single "<unavailable>" rather than the whole
object with all fields <unavailable>.
This seems good because this way the user can quickly tell whether the
whole value is unavailable, rather than having to skim all fields.
Consistency with optimized out values also seems to be a good thing to
have.
A few updates to gdb.trace/unavailable.exp where required.
Tested on x86_64 Fedora 17, native gdbserver.
gdb/
2013-11-28 Andrew Burgess <aburgess@broadcom.com>
Pedro Alves <palves@redhat.com>
* valprint.c (value_check_printable): If the value is entirely
unavailable, print a single "<unavailable>" instead of printing
all subfields.
gdb/testsuite/
2013-11-28 Andrew Burgess <aburgess@broadcom.com>
* gdb.trace/unavailable.exp (gdb_collect_args_test): Update
expected results.
(gdb_collect_locals_test): Likewise.
(gdb_collect_globals_test): Likewise.
The stop_reason != UNWIND_NO_REASON doesn't currently have "set debug
frame" output. This patch makes it print the stop_reason enum value
as a string.
gdb/
2013-11-28 Pedro Alves <palves@redhat.com>
* frame.c (get_prev_frame_1) <stop_reason != UNWIND_NO_REASON>:
Add "set debug frame" output.
(frame_stop_reason_symbol_string): New function.
After the previous patch, it should be clear that the
this_frame->unwind->stop_reason check is redundant with the
outer_frame_id check just below. We can now move the frame_id_eq
comparison to the default this_frame->unwind->stop_reason callback.
Tested on x86_64 Fedora 17.
gdb/
2013-11-28 Pedro Alves <palves@redhat.com>
* frame-unwind.c (default_frame_unwind_stop_reason): Return
UNWIND_OUTERMOST if the frame's ID is outer_frame_id.
* frame.c (get_prev_frame_1): Remove outer_frame_id check.
- The UNWIND_NULL_ID check in get_prev_frame_1 used to really be
against null_frame_id, back before we had outer_frame_id. We didn't
have UNWIND_OUTERMOST when outer_frame_id was added, but we do now,
and it's more accurate.
- It used to be necessary to check for the sentinel frame explicitly
because that uses null_frame_id for frame id. Since no other frame
can have that id nowadays (it's asserted by compute_frame_id), we
don't need that explicit check.
Tested on x86_64 Fedora 17.
gdb/
2013-11-28 Pedro Alves <palves@redhat.com>
* frame.c (get_prev_frame_1): If the frame id is outer_frame_id,
set the unwind stop reason to UNWIND_OUTERMOST, not
UNWIND_NULL_ID. Remove explicit check for sentinel frame.
Another spot that missed the previous related text adjustments.
Tested on x86_64 Fedora 17.
gdb/
2013-11-28 Pedro Alves <palves@redhat.com>
* frame.c (frame_unwind_register): Say the register was "not
saved" instead of "optimized out".
Avoid false positives if the search pattern "lose" is found in path
descriptions in comments generated by the preprocessor.
See <https://sourceware.org/bugzilla/show_bug.cgi?id=16152>.
gdb/
2013-11-27 Steffen Sledz <sledz@dresearch-fe.de>
* configure.ac: Tighten Cygwin detection check.
* configure: Rebuild.
value_of_register_lazy uses the type of REGNUM in FRAME, but given
multi-arch, the arch of FRAME might be different from the previous
frame's arch, and therefore the type of register REGNUM should be
retrieved from the unwound arch. This used to be correct before the
previous change.
Tested on x86_64 Fedora 17.
gdb/
2013-11-27 Pedro Alves <palves@redhat.com>
* frame-unwind.c (frame_unwind_got_optimized): Use the type of the
register in the previous frame's arch.
"set debug frame 1" is printing "<optimized out>" for not saved
registers. That's because the unwinders are returning optimized out
not_lval values instead of optimized out lval_register values. "<not
saved>" is how val_print_optimized_out prints lval_register values.
...
- { frame_unwind_register_value (frame=0,regnum=7(rsp),...) -> <optimized out> }
+ { frame_unwind_register_value (frame=0,regnum=7(rsp),...) -> <not saved> }
...
Tested on x86_64 Fedora 17.
2013-11-27 Pedro Alves <palves@redhat.com>
* frame-unwind.c (frame_unwind_got_optimized): Return
an lval_register value instead of a not_lval value.
If a value is entirely optimized out, then there's nothing for
value_fetch_lazy to fetch. Sequences like:
if (value_lazy (retval))
value_fetch_lazy (retval);
End up allocating the value contents buffer, wasting memory, for no
use.
gdb/ChangeLog
2013-11-26 Andrew Burgess <aburgess@broadcom.com>
* value.c (allocate_optimized_out_value): Mark value as non-lazy.
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.
The MPX patch has broken the I386_XSTATE_SIZE macro. For AVX machines,
it ends up returning I386_XSTATE_SSE_SIZE. Where it first reads
I386_XSTATE_AVX_SIZE, it should have read I386_XSTATE_AVX:
#define I386_XSTATE_SIZE(XCR0) \
(((XCR0) & I386_XSTATE_BNDCFG) != 0 ? I386_XSTATE_BNDCFG_SIZE \
: (((XCR0) & I386_XSTATE_BNDREGS) != 0 ? I386_XSTATE_BNDCFG_SIZE \
- : (((XCR0) & I386_XSTATE_AVX_SIZE) != 0 ? I386_XSTATE_AVX_SIZE \
+ : (((XCR0) & I386_XSTATE_AVX) != 0 ? I386_XSTATE_AVX_SIZE \
: I386_XSTATE_SSE_SIZE)))
The patch goes a step further and improves readability of the macro,
by adding a couple other auxiliary macros.
2013-11-26 Walfred Tedeschi <walfred.tedeschi@intel.com>
* i386-xstate.h (I386_XSTATE_MPX): New Macro.
(I386_XSTATE_MPX_MASK): Makes use of I386_XSTATE_MPX.
(HAS_MPX): New macro.
(HAS_AVX): New macro.
(I386_XSTATE_SIZE): Uses HAS_MPX and HAS_AVX.
This patch teaches "disassembly" use code cache mechanism to read
target code.
gdb:
2013-11-24 Yao Qi <yao@codesourcery.com>
* disasm.c (dis_asm_read_memory): Call target_read_code
instead of target_read_memory.
Similar to stack cache, in this patch, we add
TARGET_OBJECT_CODE_MEMORY to read code from target and add a new
option "set code-cache on|off" to optimize code accesses by
using the target memory cache.
In V4:
- Remove "without affecting correctness" from NEWS and doc.
- Replace "ON" with "on" in doc.
- "access" -> "accesses".
In V3:
- Rename functions and variables.
- Update command help, doc and NEWS entry.
- Invalidate cache on option transitions, to align with
the behaviour of "stack-cache". Since cache invalidation is
transparent to users, users don't know option "stack-cache"
transitions cause code cache invalidation.
V2 was reviewed by Doug. There are some changes in V3, so I post it
here.
gdb:
2013-11-24 Yao Qi <yao@codesourcery.com>
* NEWS: Add note on new "set code-cache" option.
* target-dcache.c (code_cache_enabled_1): New variable.
(code_cache_enabled): New variable.
(show_code_cache, set_code_cache): New function.
(code_cache_enabled_p): New function.
(_initialize_target_dcache): Register command.
* target-dcache.h (code_cache_enabled_p): Declare.
* target.c (memory_xfer_partial_1):Handle
TARGET_OBJECT_CODE_MEMORY and code_cache_enabled.
(target_read_code): New function.
* target.h (enum target_object) <TARGET_OBJECT_CODE_MEMORY>:
New.
(target_read_code): Declare.
gdb/doc:
2013-11-24 Yao Qi <yao@codesourcery.com>
* gdb.texinfo (Caching Remote Data): Document new
"set/show stack-cache" option.
Hi,
This patch does some renamings on "stack-cache" related functions and
variables.
In the review to "code cache" series v2, we have some discussions on the
name of predicate function 'stack_cache_enabled', and have some options,
1 keep it unchanged, as it is already a predicate clearly,
2 rename it to stack_cache_enabled_p,
3 rename it to enable_stack_cache_p,
I choose #2, because 'stack_cache_enabled' is a predicate, but
it's better to add "_p" suffix to stress this. There are some other
similar patterns used in GDB source, such as unop_user_defined_p
and agent_loaded_p.
Then, I have to rename variable stack_cache_enabled_p to something
else. The option is "stack-cache", so I'd like to name the variable
associated with this command as "stack_cache". Similarly, the commands
associated with this command should be renamed to "set_stack_cache"
and "show_stack_cache" respectively.
gdb:
2013-11-24 Yao Qi <yao@codesourcery.com>
* target-dcache.c (stack_cache_enabled_p_1): Rename to ...
(stack_cache_enabled_1): ... this. New variable.
(stack_cache_enabled_p): Rename to ...
(stack_cache_enabled): ... this. New variable.
(set_stack_cache_enabled_p): Rename to ...
(set_stack_cache): ... this. Update caller.
(show_stack_cache_enabled_p): Rename to ...
(show_stack_cache): ... this. Update caller.
(stack_cache_enabled): Rename to ...
(stack_cache_enabled_p): ... this. Update caller.
(_initialize_target_dcache): Replace "data cache" with
"target memory cache".
* target-dcache.h (stack_cache_enabled): Remove declaration.
(stack_cache_enabled_p): Add declaration.
* cli/cli-script.c (multi_line_command_p): New function.
(recurse_read_control_structure, read_command_lines_1): Call it.
(execute_control_command): Consistently have a blank line between
each case.
PR gdb/16196:
* valprint.c (read_string): Set new variable fetchlen based on
fetchlimit and size. Use it in call to partial_memory_read.
Update comment.
PR gdb/16196:
* valprint.c (read_string): Set new variable fetchlen based on
fetchlimit and size. Use it in call to partial_memory_read.
Update comment.
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.
If value_fetch_lazy loops infinitely while unwrapping lval_register
values, it means we either somehow ended up with two frames with the
same ID in the frame chain, or some code is trying to unwind behind
get_prev_frame's back (e.g., a frame unwind sniffer trying to unwind).
In any case, it should always be an internal error to end up in this
situation.
This patch adds a check and throws an internal error if the same frame
is returned.
2013-11-22 Tom Tromey <tromey@redhat.com>
Pedro Alves <palves@redhat.com>
PR backtrace/16155
* value.c (value_fetch_lazy): Internal error if
get_frame_register_value returns the same register.
Given we already have the frame id stash, which holds the ids of all
frames in the chain, detecting corrupted stacks with wide stack cycles
with non-consecutive dup frame ids is just as cheap as just detecting
cycles in consecutive frames:
#0 frame_id1
#1 frame_id2
#2 frame_id3
#3 frame_id1
#4 frame_id2
#5 frame_id3
#6 frame_id1
... forever ...
We just need to check whether the stash already knows about a given
frame id instead of comparing the ids of the previous/this frames.
Tested on x86_64 Fedora 17.
gdb/
2013-11-22 Pedro Alves <palves@redhat.com>
Tom Tromey <tromey@redhat.com>
* frame.c (frame_stash_add): Now returns whether a frame with the
same ID was already known.
(compute_frame_id): New function, factored out from get_frame_id.
(get_frame_id): No longer lazilly compute the frame id here.
(get_prev_frame_if_no_cycle): New function. Detects wider stack
cycles.
(get_prev_frame_1): Use it instead of get_prev_frame_raw directly,
and checking for stack cycles here.
The UNWIND_SAME_ID check is done between THIS_FRAME and the next frame
when we go try to unwind the previous frame. But at this point, it's
already too late -- we ended up with two frames with the same ID in
the frame chain. Each frame having its own ID is an invariant assumed
throughout GDB. This patch applies the UNWIND_SAME_ID detection
earlier, right after the previous frame is unwound, discarding the dup
frame if a cycle is detected.
The patch includes a new test that fails before the change. Before
the patch, the test causes an infinite loop in GDB, after the patch,
the UNWIND_SAME_ID logic kicks in and makes the backtrace stop with:
Backtrace stopped: previous frame identical to this frame (corrupt stack?)
The test uses dwarf CFI to emulate a corrupted stack with a cycle. It
has a function with registers marked DW_CFA_same_value (most
importantly RSP/RIP), so that GDB computes the same ID for that frame
and its caller. IOW, something like this:
#0 - frame_id_1
#1 - frame_id_2
#2 - frame_id_3
#3 - frame_id_4
#4 - frame_id_4 <<<< outermost (UNWIND_SAME_ID).
(The test's code is just a copy of dw2-reg-undefined.S /
dw2-reg-undefined.c, adjusted to use DW_CFA_same_value instead of
DW_CFA_undefined, and to mark a different set of registers.)
The infinite loop is here, in value_fetch_lazy:
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);
}
get_frame_register_value can return a lazy register value pointing to
the next frame. This means that the register wasn't clobbered by
FRAME; the debugger should therefore retrieve its value from the next
frame.
To be clear, get_frame_register_value unwinds the value in question
from the next frame:
struct value *
get_frame_register_value (struct frame_info *frame, int regnum)
{
return frame_unwind_register_value (frame->next, regnum);
^^^^^^^^^^^
}
In other words, if we get a lazy lval_register, it should have the
frame ID of the _next_ frame, never of FRAME.
At this point in value_fetch_lazy, the whole relevant chunk of the
stack up to frame #4 has already been unwound. The loop always
"unlazies" lval_registers in the "next/innermost" direction, not in
the "prev/unwind further/outermost" direction.
So say we're looking at frame #4. get_frame_register_value in frame
#4 can return a lazy register value of frame #3. So the next
iteration, frame_find_by_id tries to read the register from frame #3.
But, since frame #4 happens to have same id as frame #3,
frame_find_by_id returns frame #4 instead. Rinse, repeat, and we have
an infinite loop.
This is an old latent problem, exposed by the recent addition of the
frame stash. Before we had a stash, frame_find_by_id(frame_id_4)
would walk over all frames starting at the current frame, and would
always find #3 first. The stash happens to return #4 instead:
struct frame_info *
frame_find_by_id (struct frame_id id)
{
struct frame_info *frame, *prev_frame;
...
/* Try using the frame stash first. Finding it there removes the need
to perform the search by looping over all frames, which can be very
CPU-intensive if the number of frames is very high (the loop is O(n)
and get_prev_frame performs a series of checks that are relatively
expensive). This optimization is particularly useful when this function
is called from another function (such as value_fetch_lazy, case
VALUE_LVAL (val) == lval_register) which already loops over all frames,
making the overall behavior O(n^2). */
frame = frame_stash_find (id);
if (frame)
return frame;
for (frame = get_current_frame (); ; frame = prev_frame)
{
gdb/
2013-11-22 Pedro Alves <palves@redhat.com>
PR 16155
* frame.c (get_prev_frame_1): Do the UNWIND_SAME_ID check between
this frame and the new previous frame, not between this frame and
the next frame.
gdb/testsuite/
2013-11-22 Pedro Alves <palves@redhat.com>
PR 16155
* gdb.dwarf2/dw2-dup-frame.S: New file.
* gdb.dwarf2/dw2-dup-frame.c: New file.
* gdb.dwarf2/dw2-dup-frame.exp: 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.
is_intlike was mostly duplicating is_integral_type, with the exception
of the handling of TYPE_CODE_PTR when parameter PTR_OK is nonzero.
This patches deletes the is_intlike function, using is_integral_type
instead, and adjusting the two locations where this function gets
called.
The code should remain strictly equivalent.
gdb/ChangeLog:
* python/py-value.c (is_intlike): Delete.
(valpy_int): Replace use of CHECK_TYPEDEF and is_intlike
by use of is_integral_type.
(valpy_long): Replace use of CHECK_TYPEDEF and is_intlike
by use of is_integral_type and check for TYPE_CODE_PTR.
This fixes the mingw build breakage reported by Pierre.
I found that the gnulib strerror module somehow requires us to pull in
the gethostname module. However, pulling in the gethostname module
makes many things break.
I've sent a bug report to gnulib.
Meanwhile, removing the strerror module should not harm gdb and fixes
the build.
I'm checking this in.
2013-11-20 Tom Tromey <tromey@redhat.com>
* gnulib/update-gnulib.sh (IMPORTED_GNULIB_MODULES): Remove
strerror module.
* gnulib/aclocal.m4: Update.
* gnulib/config.in: Update.
* gnulib/configure: Update.
* gnulib/import/Makefile.am: Update.
* gnulib/import/Makefile.in: Update.
* gnulib/import/errno.in.h: Remove.
* gnulib/import/intprops.h: Remove.
* gnulib/import/m4/errno_h.m4: Remove.
* gnulib/import/m4/gnulib-cache.m4: Update.
* gnulib/import/m4/gnulib-comp.m4: Update.
* gnulib/import/m4/strerror.m4: Remove.
* gnulib/import/m4/sys_socket_h.m4: Remove.
* gnulib/import/strerror-override.c: Remove.
* gnulib/import/strerror-override.h: Remove.
* gnulib/import/strerror.c: Remove.
* gnulib/update-gnulib.sh: Update.
