Introduce a new print setting max-depth which can be set with 'set
print max-depth DEPTH'. The default value of DEPTH is 20, but this
can also be set to unlimited.
When GDB is printing a value containing nested structures GDB will
stop descending at depth DEPTH. Here is a small example:
typedef struct s1 { int a; } s1;
typedef struct s2 { s1 b; } s2;
typedef struct s3 { s2 c; } s3;
typedef struct s4 { s3 d; } s4;
s4 var = { { { { 3 } } } };
The following table shows how various depth settings affect printing
of 'var':
| Depth Setting | Result of 'p var' |
|---------------+--------------------------------|
| Unlimited | $1 = {d = {c = {b = {a = 3}}}} |
| 4 | $1 = {d = {c = {b = {a = 3}}}} |
| 3 | $1 = {d = {c = {b = {...}}}} |
| 2 | $1 = {d = {c = {...}}} |
| 1 | $1 = {d = {...}} |
| 0 | $1 = {...} |
Only structures, unions, and arrays are replaced in this way, scalars
and strings are not replaced.
The replacement is counted from the level at which you print, not from
the top level of the structure. So, consider the above example and
this GDB session:
(gdb) set print max-depth 2
(gdb) p var
$1 = {d = {c = {...}}}
(gdb) p var.d
$2 = {c = {b = {...}}}
(gdb) p var.d.c
$3 = {b = {a = 3}}
Setting the max-depth to 2 doesn't prevent the user from exploring
deeper into 'var' by asking for specific sub-fields to be printed.
The motivation behind this feature is to try and give the user more
control over how much is printed when examining large, complex data
structures.
The default max-depth of 20 means that there is a change in GDB's
default behaviour. Someone printing a data structure with 20 levels
of nesting will now see '{...}' instead of their data, they would need
to adjust the max depth, or call print again naming a specific field
in order to dig deeper into their data structure. If this is
considered a problem then we could increase the default, or even make
the default unlimited.
This commit relies on the previous commit, which added a new field to
the language structure, this new field was a string that contained the
pattern that should be used when a structure/union/array is replaced
in the output, this allows languages to use a syntax that is more
appropriate, mostly this will be selecting the correct types of
bracket '(...)' or '{...}', both of which are currently in use.
This commit should have no impact on MI output, expressions are
printed through the MI using -var-create and then -var-list-children.
As each use of -var-list-children only ever displays a single level of
an expression then the max-depth setting will have no impact.
This commit also adds the max-depth mechanism to the scripting
language pretty printers following basically the same rules as for the
built in value printing.
One quirk is that when printing a value using the display hint 'map',
if the keys of the map are structs then GDB will hide the keys one
depth level after it hides the values, this ensures that GDB produces
output like this:
$1 = map_object = {[{key1}] = {...}, [{key2}] = {...}}
Instead of this less helpful output:
$1 = map_object = {[{...}] = {...}, [{...}] = {...}}
This is covered by the new tests in gdb.python/py-nested-maps.exp.
gdb/ChangeLog:
* cp-valprint.c (cp_print_value_fields): Allow an additional level
of depth when printing anonymous structs or unions.
* guile/scm-pretty-print.c (gdbscm_apply_val_pretty_printer):
Don't print either the top-level value, or the children if the
max-depth is exceeded.
(ppscm_print_children): When printing the key of a map, allow one
extra level of depth.
* python/py-prettyprint.c (gdbpy_apply_val_pretty_printer): Don't
print either the top-level value, or the children if the max-depth
is exceeded.
(print_children): When printing the key of a map, allow one extra
level of depth.
* python/py-value.c (valpy_format_string): Add max_depth keyword.
* valprint.c: (PRINT_MAX_DEPTH_DEFAULT): Define.
(user_print_options): Initialise max_depth field.
(val_print_scalar_or_string_type_p): New function.
(val_print): Check to see if the max depth has been reached.
(val_print_check_max_depth): Define new function.
(show_print_max_depth): New function.
(_initialize_valprint): Add 'print max-depth' option.
* valprint.h (struct value_print_options) <max_depth>: New field.
(val_print_check_max_depth): Declare new function.
* NEWS: Document new feature.
gdb/doc/ChangeLog:
* gdb.texinfo (Print Settings): Document 'print max-depth'.
* guile.texi (Guile Pretty Printing API): Document that 'print
max-depth' can effect the display of a values children.
* python.texi (Pretty Printing API): Likewise.
(Values From Inferior): Document max_depth keyword.
gdb/testsuite/ChangeLog:
* gdb.base/max-depth.c: New file.
* gdb.base/max-depth.exp: New file.
* gdb.python/py-nested-maps.c: New file.
* gdb.python/py-nested-maps.exp: New file.
* gdb.python/py-nested-maps.py: New file.
* gdb.python/py-format-string.exp (test_max_depth): New proc.
(test_all_common): Call test_max_depth.
* gdb.fortran/max-depth.exp: New file.
* gdb.fortran/max-depth.f90: New file.
* gdb.go/max-depth.exp: New file.
* gdb.go/max-depth.go: New file.
* gdb.modula2/max-depth.exp: New file.
* gdb.modula2/max-depth.c: New file.
* lib/gdb.exp (get_print_expr_at_depths): New proc.
This commit applies all changes made after running the gdb/copyright.py
script.
Note that one file was flagged by the script, due to an invalid
copyright header
(gdb/unittests/basic_string_view/element_access/char/empty.cc).
As the file was copied from GCC's libstdc++-v3 testsuite, this commit
leaves this file untouched for the time being; a patch to fix the header
was sent to gcc-patches first.
gdb/ChangeLog:
Update copyright year range in all GDB files.
This applies the second part of GDB's End of Year Procedure, which
updates the copyright year range in all of GDB's files.
gdb/ChangeLog:
Update copyright year range in all GDB files.
This commit changes GDB to track thread numbers per-inferior. Then,
if you're debugging multiple inferiors, GDB displays
"inferior-num.thread-num" instead of just "thread-num" whenever it
needs to display a thread:
(gdb) info inferiors
Num Description Executable
1 process 6022 /home/pedro/gdb/tests/threads
* 2 process 6037 /home/pedro/gdb/tests/threads
(gdb) info threads
Id Target Id Frame
1.1 Thread 0x7ffff7fc2740 (LWP 6022) "threads" (running)
1.2 Thread 0x7ffff77c0700 (LWP 6028) "threads" (running)
1.3 Thread 0x7ffff7fc2740 (LWP 6032) "threads" (running)
2.1 Thread 0x7ffff7fc1700 (LWP 6037) "threads" (running)
2.2 Thread 0x7ffff77c0700 (LWP 6038) "threads" (running)
* 2.3 Thread 0x7ffff7fc2740 (LWP 6039) "threads" (running)
(gdb)
...
(gdb) thread 1.1
[Switching to thread 1.1 (Thread 0x7ffff7fc2740 (LWP 8155))]
(gdb)
...
etc.
You can still use "thread NUM", in which case GDB infers you're
referring to thread NUM of the current inferior.
The $_thread convenience var and Python's InferiorThread.num attribute
are remapped to the new per-inferior thread number. It's a backward
compatibility break, but since it only matters when debugging multiple
inferiors, I think it's worth doing.
Because MI thread IDs need to be a single integer, we keep giving
threads a global identifier, _in addition_ to the per-inferior number,
and make MI always refer to the global thread IDs. IOW, nothing
changes from a MI frontend's perspective.
Similarly, since Python's Breakpoint.thread and Guile's
breakpoint-thread/set-breakpoint-thread breakpoint methods need to
work with integers, those are adjusted to work with global thread IDs
too. Follow up patches will provide convenient means to access
threads' global IDs.
To avoid potencially confusing users (which also avoids updating much
of the testsuite), if there's only one inferior and its ID is "1",
IOW, the user hasn't done anything multi-process/inferior related,
then the "INF." part of thread IDs is not shown. E.g,.:
(gdb) info inferiors
Num Description Executable
* 1 process 15275 /home/pedro/gdb/tests/threads
(gdb) info threads
Id Target Id Frame
* 1 Thread 0x7ffff7fc1740 (LWP 15275) "threads" main () at threads.c:40
(gdb) add-inferior
Added inferior 2
(gdb) info threads
Id Target Id Frame
* 1.1 Thread 0x7ffff7fc1740 (LWP 15275) "threads" main () at threads.c:40
(gdb)
No regressions on x86_64 Fedora 20.
gdb/ChangeLog:
2016-01-13 Pedro Alves <palves@redhat.com>
* NEWS: Mention that thread IDs are now per inferior and global
thread IDs.
* Makefile.in (SFILES): Add tid-parse.c.
(COMMON_OBS): Add tid-parse.o.
(HFILES_NO_SRCDIR): Add tid-parse.h.
* ada-tasks.c: Adjust to use ptid_to_global_thread_id.
* breakpoint.c (insert_breakpoint_locations)
(remove_threaded_breakpoints, bpstat_check_breakpoint_conditions)
(print_one_breakpoint_location, set_longjmp_breakpoint)
(check_longjmp_breakpoint_for_call_dummy)
(set_momentary_breakpoint): Adjust to use global IDs.
(find_condition_and_thread, watch_command_1): Use parse_thread_id.
(until_break_command, longjmp_bkpt_dtor)
(breakpoint_re_set_thread, insert_single_step_breakpoint): Adjust
to use global IDs.
* dummy-frame.c (pop_dummy_frame_bpt): Adjust to use
ptid_to_global_thread_id.
* elfread.c (elf_gnu_ifunc_resolver_stop): Likewise.
* gdbthread.h (struct thread_info): Rename field 'num' to
'global_num. Add new fields 'per_inf_num' and 'inf'.
(thread_id_to_pid): Rename thread_id_to_pid to
global_thread_id_to_ptid.
(pid_to_thread_id): Rename to ...
(ptid_to_global_thread_id): ... this.
(valid_thread_id): Rename to ...
(valid_global_thread_id): ... this.
(find_thread_id): Rename to ...
(find_thread_global_id): ... this.
(ALL_THREADS, ALL_THREADS_BY_INFERIOR): Declare.
(print_thread_info): Add comment.
* tid-parse.h: New file.
* tid-parse.c: New file.
* infcmd.c (step_command_fsm_prepare)
(step_command_fsm_should_stop): Adjust to use the global thread
ID.
(until_next_command, until_next_command)
(finish_command_fsm_should_stop): Adjust to use the global thread
ID.
(attach_post_wait): Adjust to check the inferior number too.
* inferior.h (struct inferior) <highest_thread_num>: New field.
* infrun.c (handle_signal_stop)
(insert_exception_resume_breakpoint)
(insert_exception_resume_from_probe): Adjust to use the global
thread ID.
* record-btrace.c (record_btrace_open): Use global thread IDs.
* remote.c (process_initial_stop_replies): Also consider the
inferior number.
* target.c (target_pre_inferior): Clear the inferior's highest
thread num.
* thread.c (clear_thread_inferior_resources): Adjust to use the
global thread ID.
(new_thread): New inferior parameter. Adjust to use it. Set both
the thread's global ID and the thread's per-inferior ID.
(add_thread_silent): Adjust.
(find_thread_global_id): New.
(find_thread_id): Make static. Adjust to rename.
(valid_thread_id): Rename to ...
(valid_global_thread_id): ... this.
(pid_to_thread_id): Rename to ...
(ptid_to_global_thread_id): ... this.
(thread_id_to_pid): Rename to ...
(global_thread_id_to_ptid): ... this. Adjust.
(first_thread_of_process): Adjust.
(do_captured_list_thread_ids): Adjust to use global thread IDs.
(should_print_thread): New function.
(print_thread_info): Rename to ...
(print_thread_info_1): ... this, and add new show_global_ids
parameter. Handle it. Iterate over inferiors.
(print_thread_info): Reimplement as wrapper around
print_thread_info_1.
(show_inferior_qualified_tids): New function.
(print_thread_id): Use it.
(tp_array_compar): Compare inferior numbers too.
(thread_apply_command): Use tid_range_parser.
(do_captured_thread_select): Use parse_thread_id.
(thread_id_make_value): Adjust.
(_initialize_thread): Adjust "info threads" help string.
* varobj.c (struct varobj_root): Update comment.
(varobj_create): Adjust to use global thread IDs.
(value_of_root_1): Adjust to use global_thread_id_to_ptid.
* windows-tdep.c (display_tib): No longer accept an argument.
* cli/cli-utils.c (get_number_trailer): Make extern.
* cli/cli-utils.h (get_number_trailer): Declare.
(get_number_const): Adjust documentation.
* mi/mi-cmd-var.c (mi_cmd_var_update_iter): Adjust to use global
thread IDs.
* mi/mi-interp.c (mi_new_thread, mi_thread_exit)
(mi_on_normal_stop, mi_output_running_pid, mi_on_resume):
* mi/mi-main.c (mi_execute_command, mi_cmd_execute): Likewise.
* guile/scm-breakpoint.c (gdbscm_set_breakpoint_thread_x):
Likewise.
* python/py-breakpoint.c (bppy_set_thread): Likewise.
* python/py-finishbreakpoint.c (bpfinishpy_init): Likewise.
* python/py-infthread.c (thpy_get_num): Add comment and return the
per-inferior thread ID.
(thread_object_getset): Update comment of "num".
gdb/testsuite/ChangeLog:
2016-01-07 Pedro Alves <palves@redhat.com>
* gdb.base/break.exp: Adjust to output changes.
* gdb.base/hbreak2.exp: Likewise.
* gdb.base/sepdebug.exp: Likewise.
* gdb.base/watch_thread_num.exp: Likewise.
* gdb.linespec/keywords.exp: Likewise.
* gdb.multi/info-threads.exp: Likewise.
* gdb.threads/thread-find.exp: Likewise.
* gdb.multi/tids.c: New file.
* gdb.multi/tids.exp: New file.
gdb/doc/ChangeLog:
2016-01-07 Pedro Alves <palves@redhat.com>
* gdb.texinfo (Threads): Document per-inferior thread IDs,
qualified thread IDs, global thread IDs and thread ID lists.
(Set Watchpoints, Thread-Specific Breakpoints): Adjust to refer to
thread IDs.
(Convenience Vars): Document the $_thread convenience variable.
(Ada Tasks): Adjust to refer to thread IDs.
(GDB/MI Async Records, GDB/MI Thread Commands, GDB/MI Ada Tasking
Commands, GDB/MI Variable Objects): Update to mention global
thread IDs.
* guile.texi (Breakpoints In Guile)
<breakpoint-thread/set-breakpoint-thread breakpoint>: Mention
global thread IDs instead of thread IDs.
* python.texi (Threads In Python): Adjust documentation of
InferiorThread.num.
(Breakpoint.thread): Mention global thread IDs instead of thread
IDs.
https://sourceware.org/ml/gdb-patches/2014-05/msg00737.html
Currently a MEMORY_ERROR raised during unwinding a frame will cause the
unwind to stop with an error message, for example:
(gdb) bt
#0 breakpt () at amd64-invalid-stack-middle.c:27
#1 0x00000000004008f0 in func5 () at amd64-invalid-stack-middle.c:32
#2 0x0000000000400900 in func4 () at amd64-invalid-stack-middle.c:38
#3 0x0000000000400910 in func3 () at amd64-invalid-stack-middle.c:44
#4 0x0000000000400928 in func2 () at amd64-invalid-stack-middle.c:50
Cannot access memory at address 0x2aaaaaab0000
However, frame #4 is marked as being the end of the stack unwind, so a
subsequent request for the backtrace looses the error message, such as:
(gdb) bt
#0 breakpt () at amd64-invalid-stack-middle.c:27
#1 0x00000000004008f0 in func5 () at amd64-invalid-stack-middle.c:32
#2 0x0000000000400900 in func4 () at amd64-invalid-stack-middle.c:38
#3 0x0000000000400910 in func3 () at amd64-invalid-stack-middle.c:44
#4 0x0000000000400928 in func2 () at amd64-invalid-stack-middle.c:50
When fetching the backtrace, or requesting the stack depth using the MI
interface the situation is even worse, the first time a request is made
we encounter the memory error and so the MI returns an error instead of
the correct result, for example:
(gdb) -stack-info-depth
^error,msg="Cannot access memory at address 0x2aaaaaab0000"
Or,
(gdb) -stack-list-frames
^error,msg="Cannot access memory at address 0x2aaaaaab0000"
However, once one of these commands has been used gdb has, internally,
walked the stack and figured that out that frame #4 is the bottom of the
stack, so the second time an MI command is tried you'll get the "expected"
result:
(gdb) -stack-info-depth
^done,depth="5"
Or,
(gdb) -stack-list-frames
^done,stack=[frame={level="0", .. snip lots .. }]
After this patch the MEMORY_ERROR encountered during the frame unwind is
attached to frame #4 as the stop reason, and is displayed in the CLI each
time the backtrace is requested. In the MI, catching the error means that
the "expected" result is returned the first time the MI command is issued.
So, from the CLI the results of the backtrace will be:
(gdb) bt
#0 breakpt () at amd64-invalid-stack-middle.c:27
#1 0x00000000004008f0 in func5 () at amd64-invalid-stack-middle.c:32
#2 0x0000000000400900 in func4 () at amd64-invalid-stack-middle.c:38
#3 0x0000000000400910 in func3 () at amd64-invalid-stack-middle.c:44
#4 0x0000000000400928 in func2 () at amd64-invalid-stack-middle.c:50
Backtrace stopped: Cannot access memory at address 0x2aaaaaab0000
Each and every time that the backtrace is requested, while the MI output
will similarly be consistently:
(gdb) -stack-info-depth
^done,depth="5"
Or,
(gdb) -stack-list-frames
^done,stack=[frame={level="0", .. snip lots .. }]
gdb/ChangeLog:
* frame.c (struct frame_info): Add stop_string field.
(get_prev_frame_always_1): Renamed from get_prev_frame_always.
(get_prev_frame_always): Old content moved into
get_prev_frame_always_1. Call get_prev_frame_always_1 inside
TRY_CATCH, handle MEMORY_ERROR exceptions.
(frame_stop_reason_string): New function definition.
* frame.h (unwind_stop_reason_to_string): Extend comment to
mention frame_stop_reason_string.
(frame_stop_reason_string): New function declaration.
* stack.c (frame_info): Switch to frame_stop_reason_string.
(backtrace_command_1): Switch to frame_stop_reason_string.
* unwind_stop_reason.def: Add UNWIND_MEMORY_ERROR.
(LAST_ENTRY): Changed to UNWIND_MEMORY_ERROR.
* guile/lib/gdb.scm: Add FRAME_UNWIND_MEMORY_ERROR to export list.
gdb/doc/ChangeLog:
* guile.texi (Frames In Guile): Mention FRAME_UNWIND_MEMORY_ERROR.
* python.texi (Frames In Python): Mention
gdb.FRAME_UNWIND_MEMORY_ERROR.
gdb/testsuite/ChangeLog:
* gdb.arch/amd64-invalid-stack-middle.exp: Update expected results.
* gdb.arch/amd64-invalid-stack-top.exp: Likewise.
gdb/doc/guile.texi (Types In Guile, Basic Guile, Frames In Guile)
(Breakpoints In Guile, Guile Printing Module)
(Guile Exception Handling, Values From Inferior In Guile)
(Objfiles In Guile, Breakpoints In Guile, Memory Ports in Guile):
Don't use @var at the beginning of a sentence.
gdb/doc/gdb.texinfo (Frame Filter Management, Trace Files)
(C Operators, Ada Tasks, Calling, Bootstrapping, ARM)
(PowerPC Embedded, Define, Annotations for Running)
(IPA Protocol Commands, Packets, General Query Packets)
(Tracepoint Packets, Notification Packets, Environment)
(Inferiors and Programs, Set Breaks, Set Catchpoints)
(Continuing and Stepping, Signals, Thread-Specific Breakpoints)
(Frames, Backtrace, Selection, Expressions, Registers)
(Trace State Variables, Built-In Func/Proc, Signaling, Files)
(Numbers, GDB/MI Async Records, GDB/MI Data Manipulation)
(Source Annotations, Using JIT Debug Info Readers, Packets)
(Stop Reply Packets, Host I/O Packets)
(Target Description Format): Don't use @var at the beginning of a
sentence.
gdb/doc/python.texi (Basic Python, Types In Python)
(Commands In Python, Frames In Python, Line Tables In Python)
(Breakpoints In Python, gdb.printing, gdb.types)
(Type Printing API): Don't use @var at the beginning of a
sentence.
