Previously, the prefixname field of struct cmd_list_element was manually
set for prefix commands. This seems verbose and error prone as it
required every single call to functions adding prefix commands to
specify the prefix name while the same information can be easily
generated.
Historically, this was not possible as the prefix field was null for
many commands, but this was fixed in commit
3f4d92ebdf by Philippe Waroquiers, so
we can rely on the prefix field being set when generating the prefix
name.
This commit also fixes a use after free in this scenario:
* A command gets created via Python (using the gdb.Command class).
The prefix name member is dynamically allocated.
* An alias to the new command is created. The alias's prefixname is set
to point to the prefixname for the original command with a direct
assignment.
* A new command with the same name as the Python command is created.
* The object for the original Python command gets freed and its
prefixname gets freed as well.
* The alias is updated to point to the new command, but its prefixname
is not updated so it keeps pointing to the freed one.
gdb/ChangeLog:
* command.h (add_prefix_cmd): Remove the prefixname argument as
it can now be generated automatically. Update all callers.
(add_basic_prefix_cmd): Ditto.
(add_show_prefix_cmd): Ditto.
(add_prefix_cmd_suppress_notification): Ditto.
(add_abbrev_prefix_cmd): Ditto.
* cli/cli-decode.c (add_prefix_cmd): Ditto.
(add_basic_prefix_cmd): Ditto.
(add_show_prefix_cmd): Ditto.
(add_prefix_cmd_suppress_notification): Ditto.
(add_prefix_cmd_suppress_notification): Ditto.
(add_abbrev_prefix_cmd): Ditto.
* cli/cli-decode.h (struct cmd_list_element): Replace the
prefixname member variable with a method which generates the
prefix name at runtime. Update all code reading the prefix
name to use the method, and remove all code setting it.
* python/py-cmd.c (cmdpy_destroyer): Remove code to free the
prefixname member as it's now a method.
(cmdpy_function): Determine if the command is a prefix by
looking at prefixlist, not prefixname.
Now that libiberty includes htab_eq_string, we can remove the
identical function from gdb.
gdb/ChangeLog
2021-05-07 Tom Tromey <tom@tromey.com>
* breakpoint.c (ambiguous_names_p): Use htab_eq_string.
* utils.c (streq_hash): Remove.
* utils.h (streq_hash): Don't declare.
* completer.c (completion_tracker::discard_completions): Update
comment.
* ada-lang.c (_initialize_ada_language): Use htab_eq_string.
Add a '--force' flag to the '-break-condition' command to be
able to force conditions.
gdb/ChangeLog:
2021-05-06 Tankut Baris Aktemur <tankut.baris.aktemur@intel.com>
* mi/mi-cmd-break.c (mi_cmd_break_condition): New function.
* mi/mi-cmds.c: Change the binding of "-break-condition" to
mi_cmd_break_condition.
* mi/mi-cmds.h (mi_cmd_break_condition): Declare.
* breakpoint.h (set_breakpoint_condition): Declare a new
overload.
* breakpoint.c (set_breakpoint_condition): New overloaded function
extracted out from ...
(condition_command): ... this.
* NEWS: Mention the change.
gdb/testsuite/ChangeLog:
2021-05-06 Tankut Baris Aktemur <tankut.baris.aktemur@intel.com>
* gdb.mi/mi-break.exp (test_forced_conditions): Add a test
for the -break-condition command's "--force" flag.
gdb/doc/ChangeLog:
2021-05-06 Tankut Baris Aktemur <tankut.baris.aktemur@intel.com>
* gdb.texinfo (GDB/MI Breakpoint Commands): Mention the
'--force' flag of the '-break-condition' command.
Give a name to each observer, this will help produce more meaningful
debug message.
gdbsupport/ChangeLog:
* observable.h (class observable) <struct observer> <observer>:
Add name parameter.
<name>: New field.
<attach>: Add name parameter, update all callers.
Change-Id: Ie0cc4664925215b8d2b09e026011b7803549fba0
Use a function_view instead of function pointer + data. Actually,
nothing uses the data anyway, but that makes iterate_over_bp_locations
more like iterate_over_breakpoints.
gdb/ChangeLog:
* breakpoint.c (iterate_over_bp_locations): Change callback to
function view, remove data parameter.
* breakpoint.h (iterate_over_bp_locations): Likewise.
* record-full.c (record_full_sync_record_breakpoints): Remove
data parameter.
Change-Id: I66cdc94a505f67bc640bcc66865fb535ee939a57
The 'create_breakpoint' function takes a 'parse_extra' argument that
determines whether the condition, thread, and force-condition
specifiers should be parsed from the extra string or be used from the
function arguments. However, for the case when 'parse_extra' is
false, there is no way to pass the force-condition specifier. This
patch adds it as a new argument.
Also, in the case when parse_extra is false, the current behavior is
as if the condition is being forced. This is a bug. The default
behavior should reject the breakpoint. See below for a demo of this
incorrect behavior. (The MI command '-break-insert' uses the
'create_breakpoint' function with parse_extra=0.)
$ gdb -q --interpreter=mi3 /tmp/simple
=thread-group-added,id="i1"
=cmd-param-changed,param="history save",value="on"
=cmd-param-changed,param="auto-load safe-path",value="/"
~"Reading symbols from /tmp/simple...\n"
(gdb)
-break-insert -c junk -f main
&"warning: failed to validate condition at location 1, disabling:\n "
&"No symbol \"junk\" in current context.\n"
^done,bkpt={number="1",type="breakpoint",disp="keep",enabled="y",addr="<MULTIPLE>",cond="junk",times="0",original-location="main",locations=[{number="1.1",enabled="N",addr="0x000000000000114e",func="main",file="/tmp/simple.c",fullname="/tmp/simple.c",line="2",thread-groups=["i1"]}]}
(gdb)
break main if junk
&"break main if junk\n"
&"No symbol \"junk\" in current context.\n"
^error,msg="No symbol \"junk\" in current context."
(gdb)
break main -force-condition if junk
&"break main -force-condition if junk\n"
~"Note: breakpoint 1 also set at pc 0x114e.\n"
&"warning: failed to validate condition at location 1, disabling:\n "
&"No symbol \"junk\" in current context.\n"
~"Breakpoint 2 at 0x114e: file /tmp/simple.c, line 2.\n"
=breakpoint-created,bkpt={number="2",type="breakpoint",disp="keep",enabled="y",addr="<MULTIPLE>",cond="junk",times="0",original-location="main",locations=[{number="2.1",enabled="N",addr="0x000000000000114e",func="main",file="/tmp/simple.c",fullname="/tmp/simple.c",line="2",thread-groups=["i1"]}]}
^done
(gdb)
After applying this patch, we get the behavior below:
(gdb)
-break-insert -c junk -f main
^error,msg="No symbol \"junk\" in current context."
This restores the behavior that is present in the existing releases.
gdb/ChangeLog:
2021-04-21 Tankut Baris Aktemur <tankut.baris.aktemur@intel.com>
* breakpoint.h (create_breakpoint): Add a new parameter,
'force_condition'.
* breakpoint.c (create_breakpoint): Use the 'force_condition'
argument when 'parse_extra' is false to check if the condition
is invalid at all of the breakpoint locations.
Update the users below.
(break_command_1)
(dprintf_command)
(trace_command)
(ftrace_command)
(strace_command)
(create_tracepoint_from_upload): Update.
* guile/scm-breakpoint.c (gdbscm_register_breakpoint_x): Update.
* mi/mi-cmd-break.c (mi_cmd_break_insert_1): Update.
* python/py-breakpoint.c (bppy_init): Update.
* python/py-finishbreakpoint.c (bpfinishpy_init): Update.
gdb/testsuite/ChangeLog:
2021-04-21 Tankut Baris Aktemur <tankut.baris.aktemur@intel.com>
* gdb.mi/mi-break.exp: Extend with checks for invalid breakpoint
conditions.
For breakpoint locations that are disabled because of an invalid
condition, CLI displays "N*" in the 'enabled' field, where '*' refers
to the footnote below the table:
(*): Breakpoint condition is invalid at this location.
This is not necessary for MI, where we shall simply print "N" without
the footnote.
Update the document to mention the "N" value for the MI. Also remove
the line about the 'enable' field, because there is no such field for
locations.
gdb/ChangeLog:
2021-04-21 Tankut Baris Aktemur <tankut.baris.aktemur@intel.com>
* breakpoint.c (print_one_breakpoint_location): Display "N" for
disabled-by-condition locations on MI-like output.
(breakpoint_1): Do not display the disabled-by-condition footnote
if the output is MI-like.
gdb/doc/ChangeLog:
2021-04-21 Tankut Baris Aktemur <tankut.baris.aktemur@intel.com>
* gdb.texinfo (GDB/MI Breakpoint Information): Update the
description for the 'enabled' field of breakpoint locations.
The current_top_target function is a hidden dependency on the current
inferior. Since I'd like to slowly move towards reducing our dependency
on the global current state, remove this function and make callers use
current_inferior ()->top_target ()
There is no expected change in behavior, but this one step towards
making those callers use the inferior from their context, rather than
refer to the global current inferior.
gdb/ChangeLog:
* target.h (current_top_target): Remove, make callers use the
current inferior instead.
* target.c (current_top_target): Remove.
Change-Id: Iccd457036f84466cdaa3865aa3f9339a24ea001d
This adds an expr::operation_up to struct expression, and then
modifies various parts of GDB to use this member when it is non-null.
The list of such spots was a bit surprising to me, and found only
after writing most of the code and then noticing what no longer
compiled.
In a few spots, new accessor methods are added to operation
subclasses, so that code that dissects an expression will work with
the new scheme.
After this change, code that constructs an expression can be switched
to the new form without breaking.
gdb/ChangeLog
2021-03-08 Tom Tromey <tom@tromey.com>
* ada-exp.h (class ada_var_value_operation) <get_symbol>: Remove;
now in superclass.
* value.h (fetch_subexp_value): Add "op" parameter.
* value.c (init_if_undefined_command): Update.
* tracepoint.c (validate_actionline, encode_actions_1): Update.
* stap-probe.c (stap_probe::compile_to_ax): Update.
* printcmd.c (set_command): Update.
* ppc-linux-nat.c (ppc_linux_nat_target::check_condition):
Update.
* parser-defs.h (struct expr_builder) <set_operation>: New
method.
* parse.c (parse_exp_in_context, exp_uses_objfile): Update.
* expression.h (struct expression) <first_opcode>: Update.
<op>: New member.
* expprint.c (dump_raw_expression, dump_prefix_expression):
Update.
* expop.h (class var_value_operation) <get_symbol>: New method.
(class register_operation) <get_name>: New method.
(class equal_operation): No longer a typedef, now a subclass.
(class unop_memval_operation) <get_type>: New method.
(class assign_operation) <get_lhs>: New method.
(class unop_cast_operation) <get_type>: New method.
* eval.c (evaluate_expression, evaluate_type)
(evaluate_subexpression_type): Update.
(fetch_subexp_value): Add "op" parameter.
(parse_and_eval_type): Update.
* dtrace-probe.c (dtrace_probe::compile_to_ax): Update.
* breakpoint.c (update_watchpoint, watchpoint_check)
(watchpoint_exp_is_const, watch_command_1): Update.
* ax-gdb.c (gen_trace_for_expr, gen_eval_for_expr, gen_printf):
Update.
Add a new obj_section function to bound_minimal_symbol, this just
calls obj_section on the contained minimal_symbol passing in the
contained objfile.
This allows some minor code simplification in a few places.
There should be no user visible changes after this commit.
gdb/ChangeLog:
* breakpoint.c (resolve_sal_pc): Make use of
bound_minimal_symbol::obj_section.
* maint.c (maintenance_translate_address): Likewise.
* minsyms.c (minimal_symbol_upper_bound): Likewise.
* minsyms.h (struct bound_minimal_symbol) <obj_section>: New
member function.
* printcmd.c (info_address_command): Make use of
bound_minimal_symbol::obj_section.
The test-case nextoverthrow.exp is failing on targets with unstripped libc.
This is a regression since commit 1940319c0e "[gdb] Fix internal-error in
process_event_stop_test".
The problem is that this code in create_exception_master_breakpoint:
...
for (objfile *sepdebug = obj->separate_debug_objfile;
sepdebug != nullptr; sepdebug = sepdebug->separate_debug_objfile)
if (create_exception_master_breakpoint_hook (sepdebug))
...
iterates over all the separate debug object files, but fails to handle the
case that obj itself has the debug info we're looking for.
Fix this by using the separate_debug_objfiles () range instead, which does
iterate both over obj and the obj->separate_debug_objfile chain.
Tested on x86_64-linux.
gdb/ChangeLog:
2021-02-05 Tom de Vries <tdevries@suse.de>
PR breakpoints/27330
* breakpoint.c (create_exception_master_breakpoint): Handle case that
glibc object file has debug info.
When running test-case gdb.base/longjmp.exp with target board unix/-m32, we
run into:
...
(gdb) next^M
Warning:^M
Cannot insert breakpoint 0.^M
Cannot access memory at address 0x7dbf7353^M
^M
__libc_siglongjmp (env=0x804a040 <env>, val=1) at longjmp.c:28^M
28 longjmps++;^M
(gdb) FAIL: gdb.base/longjmp.exp: next over longjmp(1)
...
The failure to access memory happens in i386_get_longjmp_target and is due to
glibc having pointer encryption (aka "pointer mangling" or "pointer guard") of
the long jump buffer. This is a known problem.
In create_longjmp_master_breakpoint (which attempts to install a master
longjmp breakpoint) a preference scheme is present, which installs a
probe breakpoint if a libc:longjmp probe is present, and otherwise falls back
to setting breakpoints at the names in the longjmp_names array.
But in fact, both the probe breakpoint and the longjmp_names breakpoints are
set. The latter ones are set when processing libc.so.debug, and the former
one when processing libc.so. In other words, this is the longjmp variant of
PR26881, which describes the same problem for master exception breakpoints.
This problem only triggers when the glibc debug info package is installed,
which is not due to the debug info itself in libc.so.debug, but due to the
minimal symbols (because create_longjmp_master_breakpoint uses minimal symbols
to translate the longjmp_names to addresses).
The problem doesn't trigger for -m64, because there tdep->jb_pc_offset is not
set.
Fix this similar to commit 1940319c0e (the fix for PR26881): only install
longjmp_names breakpoints in libc.so/libc.so.debug if installing the
libc:longjmp probe in libc.so failed.
Tested on x86_64-linux.
gdb/ChangeLog:
2021-01-28 Tom de Vries <tdevries@suse.de>
PR breakpoints/27205
* breakpoint.c (create_longjmp_master_breakpoint_probe)
(create_longjmp_master_breakpoint_names): New function, factored out
of ...
(create_longjmp_master_breakpoint): ... here. Only try to install
longjmp_names breakpoints in libc.so/libc.so.debug if installing probe
breakpoint in libc.so failed.
The function create_exception_master_breakpoint in gdb/breakpoint.c attempts
to set a master exception breakpoint in each objfile. It tries this using
a libgcc/unwind probe, and if that fails then using the
_Unwind_DebugHook symbol:
...
for (objfile *objfile : current_program_space->objfiles ())
{
/* Try using probes. */
if (/* successful */)
continue;
/* Try using _Unwind_DebugHook */
}
...
The preference scheme works ok both if the objfile has debug info, and if it's
stripped.
But it doesn't work when the objfile has a .gnu_debuglink to a .debug file
(and the .debug file is present). What happens is that:
- we first encounter objfile libgcc.debug
- we try using probes, and this fails
- so we try _Unwind_DebugHook, which succeeds
- next we encounter objfile libgcc
- we try using probes, and this succeeds.
So, we end up with a master exception breakpoint in both libgcc (using probes)
and libgcc.debug (using _Unwind_DebugHook).
This eventually causes:
...
(gdb) PASS: gdb.cp/nextoverthrow.exp: post-check - next over a throw 3
next^M
src/gdb/infrun.c:6384: internal-error: \
void process_event_stop_test(execution_control_state*): \
Assertion `ecs->event_thread->control.exception_resume_breakpoint != NULL' \
failed.^M
A problem internal to GDB has been detected,^M
further debugging may prove unreliable.^M
Quit this debugging session? (y or n) FAIL: gdb.cp/nextoverthrow.exp: next
past catch (GDB internal error)
...
To trigger this internal-error, we need to use gcc-10 or later to compile the
test-case, such that it contains the fix for gcc PR97774 - "Incorrect line
info for try/catch".
Fix this by only trying to install the master exception breakpoint in
libgcc.debug using the _Unwind_DebugHook method, if the install using probes
in libgcc failed.
Tested on x86_64-linux.
gdb/ChangeLog:
2021-01-08 Tom de Vries <tdevries@suse.de>
PR gdb/26881
* breakpoint.c (create_exception_master_breakpoint_probe)
(create_exception_master_breakpoint_hook): Factor out
of ...
(create_exception_master_breakpoint): ... here. Only try to install
the master exception breakpoint in objfile.debug using the
_Unwind_DebugHook method, if the install using probes in objfile
failed.
This commits the result of running gdb/copyright.py as per our Start
of New Year procedure...
gdb/ChangeLog
Update copyright year range in copyright header of all GDB files.
This changes bp_location to derive from refcounted_object, introduces
a ref_ptr specialization for this type, and then changes
bpstats::bp_location_at to use that specialization. This removes some
manual reference counting and simplifies the code.
gdb/ChangeLog
2020-12-11 Tom Tromey <tom@tromey.com>
* inline-frame.c (stopped_by_user_bp_inline_frame): Update.
* ada-lang.c (check_status_exception): Update.
* breakpoint.c (free_bp_location): Remove.
(decref_bp_location): Use bp_location_ref_policy.
(bpstats::bpstats): Don't call incref_bp_location.
(bpstats::~bpstats): Remove.
(bpstats::bpstats): Update.
(bpstat_check_watchpoint, bpstat_check_breakpoint_conditions)
(bp_location::bp_location): Update.
(incref_bp_location): Remove.
(bkpt_print_it): Update.
* breakpoint.h (class bp_location): Derive from
refcounted_object.
(struct bpstats): Remove destructor.
<bp_location_at>: Now a bp_location_ref_ptr.
<refc>: Remove.
(bp_location_ref_ptr): New typedef.
(struct bp_location_ref_policy): New.
I noticed a spurious newline on infrun debugging output. The following patch
fixes that. I'll push as obvious.
gdb/ChangeLog:
2020-12-10 Luis Machado <luis.machado@linaro.org>
* breakpoint.c (should_be_inserted): Don't output newline.
The break command's "-force-condition" flag is currently required to
be followed by the "if" keyword. This prevents flexibility when using
other keywords, e.g. "thread":
(gdb) break main -force-condition thread 1 if foo
Function "main -force-condition" not defined.
Make breakpoint pending on future shared library load? (y or [n]) n
Remove the requirement that "-force-condition" is always followed by
an "if", so that more flexibility is obtained when positioning
keywords.
gdb/ChangeLog:
2020-12-07 Tankut Baris Aktemur <tankut.baris.aktemur@intel.com>
* linespec.c (linespec_lexer_lex_keyword): The "-force-condition"
keyword may be followed by any keyword.
* breakpoint.c (find_condition_and_thread): Advance 'tok' by
'toklen' in the case for "-force-condition".
gdb/testsuite/ChangeLog:
2020-12-07 Tankut Baris Aktemur <tankut.baris.aktemur@intel.com>
* gdb.linespec/keywords.exp: Add tests to check positional
flexibility of "-force-condition".
I noticed that watchpoint_exp_is_const should return bool; this patch
implements this change.
gdb/ChangeLog
2020-11-21 Tom Tromey <tom@tromey.com>
* breakpoint.c (watchpoint_exp_is_const): Return bool.
Switch over to using new option processing mechanism for watch,
awatch, and rwatch commands. Add command completion function.
This means that expression completion now works correctly when the
-location flag is used. So previously:
(gdb) watch var.<TAB><TAB>
.... list fields of var ....
But,
(gdb) watch -location var.<TAB><TAB>
.... list all symbols ....
After this commit only the fields of 'var' are listed even when
'-location' is passed.
Another benefit of this change is that '-location' will now complete.
One thing to note is that previous these commands accepted both
'-location' or '-l' (these being synonyms). The new option scheme
doesn't really allow for official short form flags, however, it does
allow for non-ambiguous sub-strings to be used. What this means is
that currently (as these commands only have the '-location' flag) the
user can still use '-l', so there's no change there.
The interactive help text for these commands now emphasises
'-location' as the real option, but does mention that '-l' can also be
used.
gdb/ChangeLog:
* breakpoint.c (struct watch_options): New struct.
(watch_option_defs): New static global.
(make_watch_options_def_group): New function.
(watch_maybe_just_location): Convert option parsing.
(watch_command_completer): New function.
(_initialize_breakpoint): Build help text using options mechanism.
gdb/testsuite/ChangeLog:
* gdb.base/completion.exp: Add new completion tests.
A little int to bool conversion around the 'watch' type commands.
There should be no user visible changes after this commit.
gdb/ChangeLog:
* breakpoint.c (update_watchpoint): Pass 'false' not '0'.
(watch_command_1): Update parameter types. Convert locals to
bool.
(watch_command_wrapper): Change parameter type.
(watch_maybe_just_location): Change locals to bool.
(rwatch_command_wrapper): Update parameter type.
(awatch_command_wrapper): Update parameter type.
* breakpoint.h (watch_command_wrapper): Change parameter type.
(rwatch_command_wrapper): Update parameter type.
(awatch_command_wrapper): Update parameter type.
* eval.c (fetch_subexp_value): Change parameter type.
* ppc-linux-nat.c (ppc_linux_nat_target::check_condition): Pass
'false' not '0'.
* value.h (fetch_subexp_value): Change parameter type in
declaration.
Use the gdb::option framework for the '-force' flag of the 'condition'
command. This gives tab-completion ability for the flag.
gdb/ChangeLog:
2020-10-27 Tankut Baris Aktemur <tankut.baris.aktemur@intel.com>
* breakpoint.c (struct condition_command_opts): New struct.
(condition_command_option_defs): New static global.
(make_condition_command_options_def_group): New function.
(condition_completer): Update to consider the '-force' flag.
(condition_command): Use gdb::option for the '-force' flag.
gdb/testsuite/ChangeLog:
2020-10-27 Tankut Baris Aktemur <tankut.baris.aktemur@intel.com>
* gdb.base/condbreak.exp: Update the completion tests to
consider the '-force' flag.
The previous patch made it possible to define a condition if it's
valid at some locations. If the condition is invalid at all of the
locations, it's rejected. However, there may be cases where the user
knows the condition *will* be valid at a location in the future,
e.g. due to a shared library load.
To make it possible that such condition can be defined, this patch
adds an optional '-force' flag to the 'condition' command, and,
respectively, a '-force-condition' flag to the 'break'command. When
the force flag is passed, the condition is not rejected even when it
is invalid for all the current locations (note that all the locations
would be internally disabled in this case).
For instance:
(gdb) break test.c:5
Breakpoint 1 at 0x1155: file test.c, line 5.
(gdb) cond 1 foo == 42
No symbol "foo" in current context.
Defining the condition was not possible because 'foo' is not
available. The user can override this behavior with the '-force'
flag:
(gdb) cond -force 1 foo == 42
warning: failed to validate condition at location 1.1, disabling:
No symbol "foo" in current context.
(gdb) info breakpoints
Num Type Disp Enb Address What
1 breakpoint keep y <MULTIPLE>
stop only if foo == 42
1.1 N 0x0000000000001155 in main at test.c:5
Now the condition is accepted, but the location is automatically
disabled. If a future location has a context in which 'foo' is
available, that location would be enabled.
For the 'break' command, -force-condition has the same result:
(gdb) break test.c:5 -force-condition if foo == 42
warning: failed to validate condition at location 0x1169, disabling:
No symbol "foo" in current context.
Breakpoint 1 at 0x1169: file test.c, line 5.
gdb/ChangeLog:
2020-10-27 Tankut Baris Aktemur <tankut.baris.aktemur@intel.com>
* breakpoint.h (set_breakpoint_condition): Add a new bool parameter.
* breakpoint.c: Update the help text of the 'condition' and 'break'
commands.
(set_breakpoint_condition): Take a new bool parameter
to control whether condition definition should be forced even when
the condition expression is invalid in all of the current locations.
(condition_command): Update the call to 'set_breakpoint_condition'.
(find_condition_and_thread): Take the "-force-condition" flag into
account.
* linespec.c (linespec_keywords): Add "-force-condition" as an
element.
(FORCE_KEYWORD_INDEX): New #define.
(linespec_lexer_lex_keyword): Update to consider "-force-condition"
as a keyword.
* ada-lang.c (create_ada_exception_catchpoint): Ditto.
* guile/scm-breakpoint.c (gdbscm_set_breakpoint_condition_x): Ditto.
* python/py-breakpoint.c (bppy_set_condition): Ditto.
* NEWS: Mention the changes to the 'break' and 'condition' commands.
gdb/testsuite/ChangeLog:
2020-10-27 Tankut Baris Aktemur <tankut.baris.aktemur@intel.com>
* gdb.base/condbreak-multi-context.exp: Expand to test forcing
the condition.
* gdb.linespec/cpcompletion.exp: Update to consider the
'-force-condition' keyword.
* gdb.linespec/explicit.exp: Ditto.
* lib/completion-support.exp: Ditto.
gdb/doc/ChangeLog:
2020-10-27 Tankut Baris Aktemur <tankut.baris.aktemur@intel.com>
* gdb.texinfo (Set Breaks): Document the '-force-condition' flag
of the 'break'command.
* gdb.texinfo (Conditions): Document the '-force' flag of the
'condition' command.
Currently, for a conditional breakpoint, GDB checks if the condition
can be evaluated in the context of the first symtab and line (SAL).
In case of an error, defining the conditional breakpoint is aborted.
This prevents having a conditional breakpoint whose condition may
actually be meaningful for some of the location contexts. This patch
makes it possible to define conditional BPs by checking all location
contexts. If the condition is meaningful for even one context, the
breakpoint is defined. The locations for which the condition gives
errors are disabled.
The bp_location struct is introduced a new field, 'disabled_by_cond'.
This field denotes whether the location is disabled automatically
because the condition was non-evaluatable. Disabled-by-cond locations
cannot be enabled by the user. But locations that are not
disabled-by-cond can be enabled/disabled by the user manually as
before.
For a concrete example, consider 3 contexts of a function 'func'.
class Base
{
public:
int b = 20;
void func () {}
};
class A : public Base
{
public:
int a = 10;
void func () {}
};
class C : public Base
{
public:
int c = 30;
void func () {}
};
Note that
* the variable 'a' is defined only in the context of A::func.
* the variable 'c' is defined only in the context of C::func.
* the variable 'b' is defined in all the three contexts.
With the existing GDB, it's not possible to define a conditional
breakpoint at 'func' if the condition refers to 'a' or 'c':
(gdb) break func if a == 10
No symbol "a" in current context.
(gdb) break func if c == 30
No symbol "c" in current context.
(gdb) info breakpoints
No breakpoints or watchpoints.
With this patch, it becomes possible:
(gdb) break func if a == 10
warning: failed to validate condition at location 1, disabling:
No symbol "a" in current context.
warning: failed to validate condition at location 3, disabling:
No symbol "a" in current context.
Breakpoint 1 at 0x11b6: func. (3 locations)
(gdb) break func if c == 30
Note: breakpoint 1 also set at pc 0x11ce.
Note: breakpoint 1 also set at pc 0x11c2.
Note: breakpoint 1 also set at pc 0x11b6.
warning: failed to validate condition at location 1, disabling:
No symbol "c" in current context.
warning: failed to validate condition at location 2, disabling:
No symbol "c" in current context.
Breakpoint 2 at 0x11b6: func. (3 locations)
(gdb) info breakpoints
Num Type Disp Enb Address What
1 breakpoint keep y <MULTIPLE>
stop only if a == 10
1.1 N* 0x00000000000011b6 in Base::func() at condbreak-multi-context.cc:23
1.2 y 0x00000000000011c2 in A::func() at condbreak-multi-context.cc:31
1.3 N* 0x00000000000011ce in C::func() at condbreak-multi-context.cc:39
2 breakpoint keep y <MULTIPLE>
stop only if c == 30
2.1 N* 0x00000000000011b6 in Base::func() at condbreak-multi-context.cc:23
2.2 N* 0x00000000000011c2 in A::func() at condbreak-multi-context.cc:31
2.3 y 0x00000000000011ce in C::func() at condbreak-multi-context.cc:39
(*): Breakpoint condition is invalid at this location.
Here, uppercase 'N' denotes that the location is disabled because of
the invalid condition, as mentioned with a footnote in the legend of
the table. Locations that are disabled by the user are still denoted
with lowercase 'n'. Executing the code hits the breakpoints 1.2 and
2.3 as expected.
Defining a condition on an unconditional breakpoint gives the same
behavior above:
(gdb) break func
Breakpoint 1 at 0x11b6: func. (3 locations)
(gdb) cond 1 a == 10
warning: failed to validate condition at location 1.1, disabling:
No symbol "a" in current context.
warning: failed to validate condition at location 1.3, disabling:
No symbol "a" in current context.
(gdb) info breakpoints
Num Type Disp Enb Address What
1 breakpoint keep y <MULTIPLE>
stop only if a == 10
1.1 N* 0x00000000000011b6 in Base::func() at condbreak-multi-context.cc:23
1.2 y 0x00000000000011c2 in A::func() at condbreak-multi-context.cc:31
1.3 N* 0x00000000000011ce in C::func() at condbreak-multi-context.cc:39
(*): Breakpoint condition is invalid at this location.
Locations that are disabled because of a condition cannot be enabled
by the user:
...
(gdb) enable 1.1
Breakpoint 1's condition is invalid at location 1, cannot enable.
Resetting the condition enables the locations back:
...
(gdb) cond 1
Breakpoint 1's condition is now valid at location 1, enabling.
Breakpoint 1's condition is now valid at location 3, enabling.
Breakpoint 1 now unconditional.
(gdb) info breakpoints
Num Type Disp Enb Address What
1 breakpoint keep y <MULTIPLE>
1.1 y 0x00000000000011b6 in Base::func() at condbreak-multi-context.cc:23
1.2 y 0x00000000000011c2 in A::func() at condbreak-multi-context.cc:31
1.3 y 0x00000000000011ce in C::func() at condbreak-multi-context.cc:39
If a location is disabled by the user, a condition can still be defined
but the location will remain disabled even if the condition is meaningful
for the disabled location:
...
(gdb) disable 1.2
(gdb) cond 1 a == 10
warning: failed to validate condition at location 1.1, disabling:
No symbol "a" in current context.
warning: failed to validate condition at location 1.3, disabling:
No symbol "a" in current context.
(gdb) info breakpoints
Num Type Disp Enb Address What
1 breakpoint keep y <MULTIPLE>
stop only if a == 10
1.1 N* 0x00000000000011b6 in Base::func() at condbreak-multi-context.cc:23
1.2 n 0x00000000000011c2 in A::func() at condbreak-multi-context.cc:31
1.3 N* 0x00000000000011ce in C::func() at condbreak-multi-context.cc:39
(*): Breakpoint condition is invalid at this location.
The condition of a breakpoint can be changed. Locations'
enable/disable states are updated accordingly.
...
(gdb) cond 1 c == 30
warning: failed to validate condition at location 1.1, disabling:
No symbol "c" in current context.
Breakpoint 1's condition is now valid at location 3, enabling.
(gdb) info breakpoints
Num Type Disp Enb Address What
1 breakpoint keep y <MULTIPLE>
stop only if c == 30
1.1 N* 0x00000000000011b6 in Base::func() at condbreak-multi-context.cc:23
1.2 N* 0x00000000000011c2 in A::func() at condbreak-multi-context.cc:31
1.3 y 0x00000000000011ce in C::func() at condbreak-multi-context.cc:39
(*): Breakpoint condition is invalid at this location.
(gdb) cond 1 b == 20
Breakpoint 1's condition is now valid at location 1, enabling.
(gdb) info breakpoints
Num Type Disp Enb Address What
1 breakpoint keep y <MULTIPLE>
stop only if b == 20
1.1 y 0x00000000000011b6 in Base::func() at condbreak-multi-context.cc:23
1.2 n 0x00000000000011c2 in A::func() at condbreak-multi-context.cc:31
1.3 y 0x00000000000011ce in C::func() at condbreak-multi-context.cc:39
# Note that location 1.2 was disabled by the user previously.
If the condition expression is bad for all the locations, it will be
rejected.
(gdb) cond 1 garbage
No symbol "garbage" in current context.
For conditions that are invalid or valid for all the locations of a
breakpoint, the existing behavior is preserved.
Regression-tested on X86_64 Linux.
gdb/ChangeLog:
2020-10-27 Tankut Baris Aktemur <tankut.baris.aktemur@intel.com>
* breakpoint.h (class bp_location) <disabled_by_cond>: New field.
* breakpoint.c (set_breakpoint_location_condition): New function.
(set_breakpoint_condition): Disable a breakpoint location if parsing
the condition string gives an error.
(should_be_inserted): Update to consider the 'disabled_by_cond' field.
(build_target_condition_list): Ditto.
(build_target_command_list): Ditto.
(build_bpstat_chain): Ditto.
(print_one_breakpoint_location): Ditto.
(print_one_breakpoint): Ditto.
(breakpoint_1): Ditto.
(bp_location::bp_location): Ditto.
(locations_are_equal): Ditto.
(update_breakpoint_locations): Ditto.
(enable_disable_bp_num_loc): Ditto.
(init_breakpoint_sal): Use set_breakpoint_location_condition.
(find_condition_and_thread_for_sals): New static function.
(create_breakpoint): Call find_condition_and_thread_for_sals.
(location_to_sals): Call find_condition_and_thread_for_sals instead
of find_condition_and_thread.
gdb/testsuite/ChangeLog:
2020-10-27 Tankut Baris Aktemur <tankut.baris.aktemur@intel.com>
* gdb.base/condbreak-multi-context.cc: New file.
* gdb.base/condbreak-multi-context.exp: New file.
gdb/doc/ChangeLog:
2020-10-27 Tankut Baris Aktemur <tankut.baris.aktemur@intel.com>
* gdb.texinfo (Set Breaks): Document disabling of breakpoint
locations for which the breakpoint condition is invalid.
This fixes a regression introduced by the following commit:
fe053b9e85 gdb/jit: pass the jiter objfile as an argument to jit_event_handler
In the refactoring `handle_jit_event` function was changed to pass a matching
objfile pointer to the `jit_event_handler` explicitly, rather using internal
storage:
```
--- a/gdb/breakpoint.c
+++ b/gdb/breakpoint.c
@@ -5448,8 +5448,9 @@ handle_jit_event (void)
frame = get_current_frame ();
gdbarch = get_frame_arch (frame);
+ objfile *jiter = symbol_objfile (get_frame_function (frame));
- jit_event_handler (gdbarch);
+ jit_event_handler (gdbarch, jiter);
```
This was needed to add support for multiple jiters. However it has also
introduced a regression, because `get_frame_function (frame)` here may
return `nullptr`, resulting in a crash.
A more resilient way would be to use an approach mirroring
`jit_breakpoint_re_set` - to find a minimal symbol matching the
breakpoint location and use its object file. We know that this
breakpoint event comes from a breakpoint set by `jit_breakpoint_re_set`,
thus using the reverse approach should be reliable enough.
gdb/Changelog:
2020-10-14 Mihails Strasuns <mihails.strasuns@intel.com>
* breakpoint.c (handle_jit_event): Add an argument, change how
`jit_event_handler` is called.
This changes breakpoint.c to use htab_up rather than an explicit
htab_delete. This simplifies the code somewhat.
gdb/ChangeLog
2020-09-17 Tom Tromey <tom@tromey.com>
* breakpoint.c (ambiguous_names_p): Use htab_up.
Use bool instead of int in struct solib_catchpoint and in init_catchpoint &
related functions.
gdb/ChangeLog:
* breakpoint.h (init_catchpoint): Change int parameter to bool.
(add_solib_catchpoint): Likewise.
* breakpoint.c (struct solib_catchpoint) <is_load>: Change type
to bool.
(add_solib_catchpoint): Change int parameter/variable to bool.
(catch_load_or_unload): Likewise.
(init_catchpoint): Likewise.
(create_fork_vfork_event_catchpoint): Likewise.
(catch_fork_command_1): Likewise.
(catch_exec_command_1): Likewise.
Change-Id: I1faf4506e9109f3ccdd7229ba766dc7d77aa7aa0
When GDB reads commands from the input, its internal buffer is re-used
for each line. This is usually just fine because commands are
executed in order; by the time we read the next line, we are already
done with the current line. However, a problematic case is breakpoint
commands that are input from a script. The header (e.g. commands 1 2)
is overwritten with the next line before the breakpoint numbers are
processed completely.
For example, suppose we have the following script:
break main
break main
commands 1 2
print 100123
end
and source this script:
(gdb) source script.gdb
Breakpoint 1 at 0x1245: file main.cpp, line 27.
Breakpoint 2 at 0x1245: file main.cpp, line 27.
No breakpoint number 123.
Note the "No breakpoint number 123." error message. This happens
because GDB first reads "commands 1 2" into its internal buffer
buffer -> "commands 1 2"
and then starts parsing the breakpoint numbers. After parsing the first
token, the "next token" pointer is as below:
buffer -> "commands 1 2"
next-token -----------^
So, if we continue parsing, we would tokenize "2" correctly. However,
before parsing the next number, GDB reads the commands to attach them
to breakpoint 1. Reading the commands causes the buffer to be
overwritten:
buffer -> " print 100123"
next-token -----------^
So, the next time we parse the breakpoint number, we read "123".
To fix, simply create a copy of the arguments of the header.
gdb/ChangeLog:
2020-09-16 Tankut Baris Aktemur <tankut.baris.aktemur@intel.com>
* breakpoint.c (commands_command_1): Make a copy of the 'arg'
argument.
gdb/testsuite/ChangeLog:
2020-09-16 Tankut Baris Aktemur <tankut.baris.aktemur@intel.com>
* gdb.base/bp-cmds-sourced-script.c: New file.
* gdb.base/bp-cmds-sourced-script.exp: New test.
* gdb.base/bp-cmds-sourced-script.gdb: New file.
The options for the "breakpoint condition-evaluation" setting are
"host", "target", and "auto". The help message mentions the option
"gdb" at one point instead of "host". Fix this typo. Also add a period.
gdb/ChangeLog:
2020-09-11 Tankut Baris Aktemur <tankut.baris.aktemur@intel.com>
* breakpoint.c: Fix typo in the help message of the
"set breakpoint condition-evaluation" command.
Consider test-case test.c:
...
$ cat test.c
int main (void) {
return 0;
L1:
(void)0;
}
...
Compiled with debug info:
...
$ gcc test.c -g
...
When attempting to set a breakpoint at L1, which is a label without address:
...
<1><f4>: Abbrev Number: 2 (DW_TAG_subprogram)
<f5> DW_AT_name : main
<2><115>: Abbrev Number: 3 (DW_TAG_label)
<116> DW_AT_name : L1
<119> DW_AT_decl_file : 1
<11a> DW_AT_decl_line : 5
<2><11b>: Abbrev Number: 0
...
we run into an internal-error:
...
$ gdb -batch a.out -ex "b main:L1"
linespec.c:3233: internal-error: void \
decode_line_full(const event_location*, int, program_space*, symtab*, \
int, linespec_result*, const char*, const char*): \
Assertion `result.size () == 1 || canonical->pre_expanded' failed.
A problem internal to GDB has been detected,
further debugging may prove unreliable.
...
Fix this by detecting the error condition in decode_line_full instead, and
throwing an error, such that we have instead:
...
(gdb) b main:L1
Location main:L1 not available
(gdb)
...
Unfortunately, to call event_location_to_string, which is used to get the
location name in the error message, we need to pass a non-const struct
event_location, because the call may cache the string in the struct (See
EL_STRING). So, we change the prototype of decode_line_full accordingly, and
everywhere this propages to.
Tested on x86_64-linux.
gdb/ChangeLog:
2020-08-28 Tom de Vries <tdevries@suse.de>
PR breakpoint/26544
* breakpoint.c (parse_breakpoint_sals): Remove const from struct
event_location.
(create_breakpoint): Same.
(base_breakpoint_decode_location): Same.
(bkpt_create_sals_from_location): Same.
(bkpt_decode_location): Same.
(bkpt_probe_create_sals_from_location): Same.
(bkpt_probe_decode_location): Same.
(tracepoint_create_sals_from_location): Same.
(tracepoint_decode_location): Same.
(tracepoint_probe_decode_location): Same.
(strace_marker_create_sals_from_location): Same.
(strace_marker_decode_location): Same.
(create_sals_from_location_default): Same.
(decode_location_default): Same.
* breakpoint.h (struct breakpoint_ops): Same.
(create_breakpoint): Same.
* linespec.h (decode_line_full): Same.
* linespec.c (decode_line_full): Same. Throw error if
result.size () == 0.
gdb/testsuite/ChangeLog:
2020-08-28 Tom de Vries <tdevries@suse.de>
* gdb.base/label-without-address.c: New test.
* gdb.base/label-without-address.exp: New file.
If you do "advance LINESPEC", and LINESPEC expands to more than one
location, GDB just errors out:
if (sals.size () != 1)
error (_("Couldn't get information on specified line."));
For example, advancing to a line in an inlined function, inlined three
times:
(gdb) b 21
Breakpoint 1 at 0x55555555516f: advance.cc:21. (3 locations)
(gdb) info breakpoints
Num Type Disp Enb Address What
1 breakpoint keep y <MULTIPLE>
1.1 y 0x000055555555516f in inline_func at advance.cc:21
1.2 y 0x000055555555517e in inline_func at advance.cc:21
1.3 y 0x000055555555518d in inline_func at advance.cc:21
(gdb) advance 21
Couldn't get information on specified line.
(gdb)
Similar issue with the "until" command, as it shares the
implementation with "advance".
Since, as the comment in gdb.base/advance.exp says, "advance <location>"
is really just syntactic sugar for "tbreak <location>;continue",
fix this by making GDB insert a breakpoint at all the resolved
locations.
A new testcase is included, which exercises both "advance" and
"until", in two different cases expanding to multiple locations:
- inlined functions
- C++ overloads
This also exercises the inline frames issue fixed by the previous
patch.
gdb/ChangeLog:
PR gdb/26524
* breakpoint.c (until_break_fsm) <location_breakpoint,
caller_breakpoint>: Delete fields.
<breakpoints>: New field.
<until_break_fsm>: Adjust to save a breakpoint vector instead of
two individual breakpoints.
(until_break_fsm::should_stop): Loop over breakpoints in the
breakpoint vector.
(until_break_fsm::clean_up): Adjust to clear the breakpoints
vector.
(until_break_command): Handle location expanding into multiple
sals.
gdb/testsuite/ChangeLog:
PR gdb/26523
PR gdb/26524
* gdb.base/advance-until-multiple-locations.cc: New.
* gdb.base/advance-until-multiple-locations.exp: New.
Introduce this macro to print debug statements in the infrun.c file,
same idea as what was done in 9327494e0e ("gdb: add
linux_nat_debug_printf macro").
Although in this case, there are places outside infrun.c that print
debug statements if debug_infrun is set. So the macro has to be
declared in the header file, so that it can be used in these other
files.
Note one special case. In stop_all_threads, I've used an explicit
if (debug_infrun)
infrun_debug_printf_1 ("stop_all_threads", "done");
for the message in the SCOPE_EXIT. Otherwise, the message appears like
this:
[infrun] operator(): done
Until we find a better solution for extracting a meaningful function
name for lambda functions, I think it's fine to handle these special
cases manually, they are quite rare.
Some tests need to be updated, because they rely on some infrun debug
statements.
gdb/ChangeLog:
* infrun.h (infrun_debug_printf_1): New function declaration.
(infrun_debug_printf): New macro.
* infrun.c (infrun_debug_printf_1): Use infrun_debug_printf
throughout.
(infrun_debug_printf): New function.
* breakpoint.c (should_be_inserted): Use infrun_debug_printf.
(handle_jit_event): Likewise.
gdb/testsuite/ChangeLog:
* gdb.base/gdb-sigterm.exp (do_test): Update expected regexp.
* gdb.threads/signal-while-stepping-over-bp-other-thread.exp:
Likewise.
* gdb.threads/stepi-random-signal.exp: Likewise.
Change-Id: I66433c8a9caa64c8525ab57c593022b9d1956d5c
Apply minor refactoring to 'set_breakpoint_condition'.
gdb/ChangeLog:
2020-07-30 Tankut Baris Aktemur <tankut.baris.aktemur@intel.com>
* breakpoint.c (set_breakpoint_condition): Do minor refactoring.
In 'set_breakpoint_condition', GDB resets the condition expressions
before parsing the condition input by the user. This leads to the
problem of losing the condition expressions if the new condition
does not parse successfully and is thus rejected.
For instance:
$ gdb ./test
Reading symbols from ./test...
(gdb) start
Temporary breakpoint 1 at 0x114e: file test.c, line 4.
Starting program: test
Temporary breakpoint 1, main () at test.c:4
4 int a = 10;
(gdb) break 5
Breakpoint 2 at 0x555555555155: file test.c, line 5.
Now define a condition that would evaluate to false. Next, attempt
to overwrite that with an invalid condition:
(gdb) cond 2 a == 999
(gdb) cond 2 gibberish
No symbol "gibberish" in current context.
(gdb) info breakpoints
Num Type Disp Enb Address What
2 breakpoint keep y 0x0000555555555155 in main at test.c:5
stop only if a == 999
It appears as if the bad condition is successfully rejected. But if we
resume the program, we see that we hit the breakpoint although the condition
would evaluate to false.
(gdb) continue
Continuing.
Breakpoint 2, main () at test.c:5
5 a = a + 1; /* break-here */
Fix the problem by not resetting the condition expressions before
parsing the condition input.
Suppose the fix is applied. A similar problem could occur if the
condition is valid, but has "junk" at the end. In this case, parsing
succeeds, but an error is raised immediately after. It is too late,
though; the condition expression is already updated.
For instance:
$ gdb ./test
Reading symbols from ./test...
(gdb) start
Temporary breakpoint 1 at 0x114e: file test.c, line 4.
Starting program: test
Temporary breakpoint 1, main () at test.c:4
4 int a = 10;
(gdb) break 5
Breakpoint 2 at 0x555555555155: file test.c, line 5.
(gdb) cond 2 a == 999
(gdb) cond 2 a == 10 if
Junk at end of expression
(gdb) info breakpoints
Num Type Disp Enb Address What
2 breakpoint keep y 0x0000555555555155 in main at test.c:5
stop only if a == 999
(gdb) c
Continuing.
Breakpoint 2, main () at test.c:5
5 a = a + 1; /* break-here */
(gdb)
We should not have hit the breakpoint because the condition would
evaluate to false.
Fix this problem by updating the condition expression of the breakpoint
after parsing the input successfully and checking that there is no
remaining junk.
gdb/ChangeLog:
2020-07-30 Tankut Baris Aktemur <tankut.baris.aktemur@intel.com>
* breakpoint.c (set_breakpoint_condition): Update the condition
expressions after checking that the input condition string parses
successfully and does not contain junk at the end.
gdb/testsuite/ChangeLog:
2020-07-30 Tankut Baris Aktemur <tankut.baris.aktemur@intel.com>
* gdb.base/condbreak-bad.exp: Extend the test with scenarios
that attempt to overwrite an existing condition with a condition
that fails parsing and also with a condition that parses fine
but contains junk at the end.
The condition of a breakpoint can be set with the 'cond' command. If
the condition has errors that make it problematic to evaluate, it
appears like GDB rejects the condition, but updates the breakpoint's
condition string, which causes incorrect/unintuitive behavior.
For instance:
$ gdb ./test
Reading symbols from ./test...
(gdb) break 5
Breakpoint 1 at 0x1155: file test.c, line 5.
(gdb) cond 1 gibberish
No symbol "gibberish" in current context.
At this point, it looks like the condition was rejected.
But "info breakpoints" shows the following:
(gdb) info breakpoints
Num Type Disp Enb Address What
1 breakpoint keep y 0x0000000000001155 in main at test.c:5
stop only if gibberish
Running the code gives the following behavior, where re-insertion of
the breakpoint causes failures.
(gdb) run
Starting program: test
warning: failed to reevaluate condition for breakpoint 1: No symbol "gibberish" in current context.
warning: failed to reevaluate condition for breakpoint 1: No symbol "gibberish" in current context.
warning: failed to reevaluate condition for breakpoint 1: No symbol "gibberish" in current context.
warning: failed to reevaluate condition for breakpoint 1: No symbol "gibberish" in current context.
warning: failed to reevaluate condition for breakpoint 1: No symbol "gibberish" in current context.
[Inferior 1 (process 19084) exited normally]
(gdb)
This broken behavior occurs because GDB updates the condition string
of the breakpoint *before* checking that it parses successfully.
When parsing fails, the update has already taken place.
Fix the problem by updating the condition string *after* parsing the
condition. We get the following behavior when this patch is applied:
$ gdb ./test
Reading symbols from ./test...
(gdb) break 5
Breakpoint 1 at 0x1155: file test.c, line 5.
(gdb) cond 1 gibberish
No symbol "gibberish" in current context.
(gdb) info breakpoints
Num Type Disp Enb Address What
1 breakpoint keep y 0x0000000000001155 in main at test.c:5
(gdb) run
Starting program: test
Breakpoint 1, main () at test.c:5
5 a = a + 1; /* break-here */
(gdb) c
Continuing.
[Inferior 1 (process 15574) exited normally]
(gdb)
A side note: The problem does not occur if the condition is given
at the time of breakpoint definition, as in "break 5 if gibberish",
because the parsing of the condition fails during symtab-and-line
creation, before the breakpoint is created.
Finally, the code included the following comment:
/* I don't know if it matters whether this is the string the user
typed in or the decompiled expression. */
This comment did not make sense to me because the condition string is
the user-typed input. The patch updates this comment, too.
gdb/ChangeLog:
2020-07-30 Tankut Baris Aktemur <tankut.baris.aktemur@intel.com>
* breakpoint.c (set_breakpoint_condition): Update the
condition string after parsing the new condition successfully.
gdb/testsuite/ChangeLog:
2020-07-30 Tankut Baris Aktemur <tankut.baris.aktemur@intel.com>
* gdb.base/condbreak-bad.c: New test.
* gdb.base/condbreak-bad.exp: New file.
This is a refactoring that adds a new parameter to the `jit_event_handler`
function: the JITer objfile. The goal is to distinguish which JITer
triggered the JIT event, in case there are multiple JITers -- a capability
that is added in a subsequent patch.
gdb/ChangeLog:
2020-07-22 Tankut Baris Aktemur <tankut.baris.aktemur@intel.com>
* jit.h: Forward-declare `struct objfile`.
(jit_event_handler): Add a second parameter, the JITer objfile.
* jit.c (jit_read_descriptor): Change the signature to take the
JITer objfile as an argument instead of the jit_program_space_data.
(jit_inferior_init): Update the call to jit_read_descriptor.
(jit_event_handler): Use the new JITer objfile argument when calling
jit_read_descriptor.
* breakpoint.c (handle_jit_event): Update the call to
jit_event_handler to pass the JITer objfile.
This commit changes the language_data::la_watch_location_expression
function pointer member variable into a member function of
language_defn.
There should be no user visible changes after this commit.
gdb/ChangeLog:
* ada-lang.c (ada_watch_location_expression): Rename to
ada_language::watch_location_expression.
(ada_language_data): Delete la_watch_location_expression
initializer.
(ada_language::watch_location_expression): New member function,
implementation from ada_watch_location_expression.
* breakpoint.c (watch_command_1): Update call to
watch_location_expression.
* c-lang.c (c_watch_location_expression): Rename to
language_defn::watch_location_expression.
(c_language_data): Delete la_watch_location_expression
initializer.
(cplus_language_data): Likewise.
(asm_language_data): Likewise.
(minimal_language_data): Likewise.
* c-lang.h (c_watch_location_expression): Delete declaration.
* d-lang.c (d_language_data): Delete la_watch_location_expression
initializer.
* f-lang.c (f_language_data): Likewise.
* go-lang.c (go_language_data): Likewise.
* language.c (language_defn::watch_location_expression): Member
function implementation from c_watch_location_expression.
(unknown_language_data): Delete la_watch_location_expression
initializer.
(auto_language_data): Likewise.
* language.h (language_data): Delete la_watch_location_expression
field.
(language_defn::watch_location_expression): Declare new member
function.
* m2-lang.c (m2_language_data): Delete
la_watch_location_expression initializer.
* objc-lang.c (objc_language_data): Likewise.
* opencl-lang.c (opencl_language_data): Likewise.
* p-lang.c (pascal_language_data): Likewise.
* rust-lang.c (rust_watch_location_expression): Rename to
rust_language::watch_location_expression.
(rust_language_data): Delete la_watch_location_expression
initializer.
(rust_language::watch_location_expression): New member function,
implementation from rust_watch_location_expression.
In the following conditions:
- A target with hardware breakpoints available, and
- A target that uses software single stepping,
- An instruction at ADDRESS loops back to itself,
Now consider the following steps:
1. The user places a hardware breakpoint at ADDRESS (an instruction
that loops to itself),
2. The inferior runs and hits the breakpoint at ADDRESS,
3. The user tells GDB to 'continue'.
In #3 when the user tells GDB to continue, GDB first disables the
hardware breakpoint at ADDRESS, and then inserts a software
single-step breakpoint at ADDRESS. The original user-created
breakpoint was a hardware breakpoint, while the single-step breakpoint
will be a software breakpoint.
GDB continues and immediately hits the software single-step
breakpoint.
GDB then deletes the software single-step breakpoint by calling
delete_single_step_breakpoints, which eventually calls
delete_breakpoint, which, once the breakpoint (and its locations) are
deleted, calls update_global_location_list.
During update_global_location_list GDB spots that we have an old
location (the software single step breakpoint location) that is
inserted, but being deleted, and a location (the original hardware
breakpoint) at the same address which we are keeping, but which is not
currently inserted, GDB then calls breakpoint_locations_match on these
two locations.
Currently the locations do match, and so GDB calls swap_insertion
which swaps the "inserted" state of the two locations. The user
created hardware breakpoint is marked as inserted, while the GDB
internal software single step breakpoint is now marked as not
inserted. After this GDB returns through the call stack and leaves
delete_single_step_breakpoints.
After this GDB continues with its normal "stopping" process, as part
of this stopping process GDB removes all the breakpoints from the
target. Due to the swap it is now the user-created hardware
breakpoint that is marked as inserted, so it is this breakpoint GDB
tries to remove.
The problem is that GDB inserted the software single-step breakpoint
as a software breakpoint, but is now trying to remove the hardware
breakpoint. The problem is removing a software breakpoint is very
different to removing a hardware breakpoint, this could result is some
undetected undefined behaviour, or as in the original bug report (PR
gdb/25741), could result in the target throwing an error.
With "set breakpoint always-inserted on", we can easily reproduce this
against GDBserver. E.g.:
(gdb) hbreak main
Sending packet: $m400700,40#28...Packet received: 89e58b....
Sending packet: $m400736,1#fe...Packet received: 48
Hardware assisted breakpoint 1 at 0x400736: file threads.c, line 57.
Sending packet: $Z1,400736,1#48...Packet received: OK
Packet Z1 (hardware-breakpoint) is supported
(gdb) b main
Note: breakpoint 1 also set at pc 0x400736.
Sending packet: $m400736,1#fe...Packet received: 48
Breakpoint 2 at 0x400736: file threads.c, line 57.
(gdb) del
Delete all breakpoints? (y or n) y
Sending packet: $z0,400736,1#67...Packet received: E01
warning: Error removing breakpoint 2
This patch adds a testcase that does exactly that.
Trying to enhance GDB to handle this scenario while continuing to
avoid inserting redundant software and hardware breakpoints at the
same address turns out futile, because, given non-stop and breakpoints
always-inserted, if the user:
#1 - inserts a hw breakpoint, then
#2 - inserts a sw breakpoint at the same address, and then
#3 - removes the original hw breakpoint,
GDB would have to make sure to insert the sw breakpoint before
removing the hw breakpoint, to avoid running threads missing the
breakpoint. I.e., there's always going to be a window where a target
needs to be able to handle both sw and a hw breakpoints installed at
the same address. You can see more detailed description of that issue
here:
https://sourceware.org/pipermail/gdb-patches/2020-April/167738.html
So the fix here is to just stop considering software breakpoints and
hw breakpoints duplicates, and let GDB insert sw and hw breakpoints at
the same address.
The central change is to make breakpoint_locations_match consider the
location's type too. There are several other changes necessary to
actually make that that work correctly, however:
- We need to handle the duplicates detection better. Take a look at
the loop at the tail end of update_global_location_list. Currently,
because breakpoint locations aren't sorted by type, we can end up
with, at the same address, a sw break, then a hw break, then a sw
break, etc. The result is that that second sw break won't be
considered a duplicate of the first sw break. Seems like we already
handle that incorrectly for range breakpoints.
- The "set breakpoint auto-hw on" handling is moved out of
insert_bp_location to update_global_location_list, before the
duplicates determination.
Moving "set breakpoint auto-hw off" handling as well and downgrading
it to a warning+'disabling the location' was considered too, but in
the end discarded, because we want to error out with internal and
momentary breakpoints, like software single-step breakpoints.
Disabling such locations at update_global_location_list time would
make GDB lose control of the inferior.
- In update_breakpoint_locations, the logic of matching old locations
with new locations, in the have_ambiguous_names case, is updated to
still consider sw vs hw locations the same.
- Review all ALL_BP_LOCATIONS_AT_ADDR uses, and update those that
might need to be updated, and update comments for those that don't.
Note that that macro walks all locations at a given address, and
doesn't call breakpoint_locations_match.
The result against GDBserver (with "set breakpoint
condition-evaluation host" to avoid seeing confusing reinsertions) is:
(gdb) hbreak main
Sending packet: $m400736,1#fe...Packet received: 48
Hardware assisted breakpoint 1 at 0x400736: file main.c, line 57.
Sending packet: $Z1,400736,1#48...Packet received: OK
(gdb) b main
Note: breakpoint 1 also set at pc 0x400736.
Sending packet: $m400736,1#fe...Packet received: 48
Breakpoint 4 at 0x400736: file main.c, line 57.
Sending packet: $Z0,400736,1#47...Packet received: OK
(gdb) del 3
Sending packet: $z1,400736,1#68...Packet received: OK
gdb/ChangeLog:
2020-05-17 Pedro Alves <palves@redhat.com>
Andrew Burgess <andrew.burgess@embecosm.com>
Keno Fischer <keno@juliacomputing.com>
PR gdb/25741
* breakpoint.c (build_target_condition_list): Update comments.
(build_target_command_list): Update comments and skip matching
locations.
(insert_bp_location): Move "set breakpoint auto-hw on" handling to
a separate function. Simplify "set breakpoint auto-hw off"
handling.
(insert_breakpoints): Update comment.
(tracepoint_locations_match): New parameter. For breakpoints,
compare location types too, if the caller wants to.
(handle_automatic_hardware_breakpoints): New functions.
(bp_location_is_less_than): Also sort by location type and
hardware breakpoint length.
(update_global_location_list): Handle "set breakpoint auto-hw on"
here.
(update_breakpoint_locations): Ask breakpoint_locations_match to
ignore location types.
gdb/testsuite/ChangeLog:
2020-05-17 Pedro Alves <palves@redhat.com>
PR gdb/25741
* gdb.base/hw-sw-break-same-address.exp: New file.
This commit finally does the (small) change that started this patch
series.
It ensures that the class_alias is only used for user-defined aliases.
So, the few GDB pre-defined aliases that were using the 'class_alias'
class are now using a real help class, typically the class of
the aliased command.
gdb/ChangeLog
2020-05-15 Philippe Waroquiers <philippe.waroquiers@skynet.be>
* command.h (enum command_class): Improve comments, document
that class_alias is for user-defined aliases, give the class
name for each class, remove unused class_xdb.
* cli/cli-decode.c (add_com_alias): Document THECLASS intended usage.
* breakpoint.c (_initialize_breakpoint): Replace class_alias
by a precise class.
* infcmd.c (_initialize_infcmd): Likewise.
* reverse.c (_initialize_reverse): Likewise.
* stack.c (_initialize_stack): Likewise.
* symfile.c (_initialize_symfile): Likewise.
* tracepoint.c (_initialize_tracepoint): Likewise.
gdb/testsuite/ChangeLog
2020-05-15 Philippe Waroquiers <philippe.waroquiers@skynet.be>
* gdb.base/alias.exp: Verify 'help aliases' shows user defined aliases.
Remove TYPE_CODE, changing all the call sites to use type::code
directly. This is quite a big diff, but this was mostly done using sed
and coccinelle. A few call sites were done by hand.
gdb/ChangeLog:
* gdbtypes.h (TYPE_CODE): Remove. Change all call sites to use
type::code instead.
I looked at all the calls to add_prefix_cmd, and replaced them with
calls to add_basic_prefix_cmd or add_show_prefix_cmd when appropriate.
This makes gdb's command language a bit more regular. I don't think
there's a significant downside.
Note that this patch removes a couple of tests. The removed ones are
completely redundant.
gdb/ChangeLog
2020-05-03 Tom Tromey <tom@tromey.com>
* breakpoint.c (catch_command, tcatch_command): Remove.
(_initialize_breakpoint): Use add_basic_prefix_cmd,
add_show_prefix_cmd.
(set_breakpoint_cmd, show_breakpoint_cmd): Remove
* utils.c (set_internal_problem_cmd, show_internal_problem_cmd):
Remove.
(add_internal_problem_command): Use add_basic_prefix_cmd,
add_show_prefix_cmd.
* mips-tdep.c (set_mipsfpu_command): Remove.
(_initialize_mips_tdep): Use add_basic_prefix_cmd.
* dwarf2/index-cache.c (set_index_cache_command): Remove.
(_initialize_index_cache): Use add_basic_prefix_cmd.
* memattr.c (dummy_cmd): Remove.
(_initialize_mem): Use add_basic_prefix_cmd, add_show_prefix_cmd.
* tui/tui-win.c (set_tui_cmd, show_tui_cmd): Remove.
(_initialize_tui_win): Use add_basic_prefix_cmd,
add_show_prefix_cmd.
* cli/cli-logging.c (set_logging_command): Remove.
(_initialize_cli_logging): Use add_basic_prefix_cmd,
add_show_prefix_cmd.
(show_logging_command): Remove.
* target.c (target_command): Remove.
(add_target): Use add_basic_prefix_cmd.
gdb/testsuite/ChangeLog
2020-05-03 Tom Tromey <tom@tromey.com>
* gdb.base/sepdebug.exp: Remove "catch" test.
* gdb.base/break.exp: Remove "catch" test.
* gdb.base/default.exp: Update expected output.
Currently there are many prefix commands that do nothing but call
either help_list or cmd_show_list. I happened to notice that one such
call, for "set print type", used the wrong command list parameter,
causing incorrect output.
Rather than fix this bug in isolation, I decided to eliminate this
possibility by adding two new ways to add prefix commands, which
simply route the call to help_list or cmd_show_list, as appropriate.
This makes it impossible for a mismatch to occur.
In some cases, a bit of output was removed; however, I don't think
this output in general was very useful. It seemed redundant with
what's already printed by help_list. A representative example is this
hunk, removed from ada-lang.c:
- printf_unfiltered (_(\
-"\"set ada\" must be followed by the name of a setting.\n"));
This simplified the CLI style set/show commands quite a bit, and
allowed the deletion of a macro.
This also cleans up some unusual code in windows-tdep.c.
Tested on x86-64 Fedora 30. Note that I have no way to build the
go32-nat.c change.
gdb/ChangeLog
2020-04-17 Tom Tromey <tromey@adacore.com>
* auto-load.c (show_auto_load_cmd): Remove.
(auto_load_show_cmdlist_get): Use add_show_prefix_cmd.
* arc-tdep.c (_initialize_arc_tdep): Use add_show_prefix_cmd.
(maintenance_print_arc_command): Remove.
* tui/tui-win.c (tui_command): Remove.
(tui_get_cmd_list): Use add_basic_prefix_cmd.
* tui/tui-layout.c (tui_layout_command): Remove.
(_initialize_tui_layout): Use add_basic_prefix_cmd.
* python/python.c (user_set_python, user_show_python): Remove.
(_initialize_python): Use add_basic_prefix_cmd,
add_show_prefix_cmd.
* guile/guile.c (set_guile_command, show_guile_command): Remove.
(install_gdb_commands): Use add_basic_prefix_cmd,
add_show_prefix_cmd.
(info_guile_command): Remove.
* dwarf2/read.c (set_dwarf_cmd, show_dwarf_cmd): Remove.
(_initialize_dwarf2_read): Use add_basic_prefix_cmd,
add_show_prefix_cmd.
* cli/cli-style.h (class cli_style_option) <add_setshow_commands>:
Remove do_set and do_show parameters.
* cli/cli-style.c (set_style, show_style): Remove.
(_initialize_cli_style): Use add_basic_prefix_cmd,
add_show_prefix_cmd.
(cli_style_option::add_setshow_commands): Remove do_set and
do_show parameters.
(cli_style_option::add_setshow_commands): Use
add_basic_prefix_cmd, add_show_prefix_cmd.
(STYLE_ADD_SETSHOW_COMMANDS): Remove macro.
(set_style_name): Remove.
* cli/cli-dump.c (dump_command, append_command): Remove.
(srec_dump_command, ihex_dump_command, verilog_dump_command)
(tekhex_dump_command, binary_dump_command)
(binary_append_command): Remove.
(_initialize_cli_dump): Use add_basic_prefix_cmd.
* windows-tdep.c (w32_prefix_command_valid): Remove global.
(init_w32_command_list): Remove; move into ...
(_initialize_windows_tdep): ... here. Use add_basic_prefix_cmd.
* valprint.c (set_print, show_print, set_print_raw)
(show_print_raw): Remove.
(_initialize_valprint): Use add_basic_prefix_cmd,
add_show_prefix_cmd.
* typeprint.c (set_print_type, show_print_type): Remove.
(_initialize_typeprint): Use add_basic_prefix_cmd,
add_show_prefix_cmd.
* record.c (set_record_command, show_record_command): Remove.
(_initialize_record): Use add_basic_prefix_cmd,
add_show_prefix_cmd.
* cli/cli-cmds.c (_initialize_cli_cmds): Use add_basic_prefix_cmd,
add_show_prefix_cmd.
(info_command, show_command, set_debug, show_debug): Remove.
* top.h (set_history, show_history): Don't declare.
* top.c (set_history, show_history): Remove.
* target-descriptions.c (set_tdesc_cmd, show_tdesc_cmd)
(unset_tdesc_cmd): Remove.
(_initialize_target_descriptions): Use add_basic_prefix_cmd,
add_show_prefix_cmd.
* symtab.c (info_module_command): Remove.
(_initialize_symtab): Use add_basic_prefix_cmd.
* symfile.c (overlay_command): Remove.
(_initialize_symfile): Use add_basic_prefix_cmd.
* sparc64-tdep.c (info_adi_command): Remove.
(_initialize_sparc64_adi_tdep): Use add_basic_prefix_cmd.
* sh-tdep.c (show_sh_command, set_sh_command): Remove.
(_initialize_sh_tdep): Use add_basic_prefix_cmd,
add_show_prefix_cmd.
* serial.c (serial_set_cmd, serial_show_cmd): Remove.
(_initialize_serial): Use add_basic_prefix_cmd,
add_show_prefix_cmd.
* ser-tcp.c (set_tcp_cmd, show_tcp_cmd): Remove.
(_initialize_ser_tcp): Use add_basic_prefix_cmd,
add_show_prefix_cmd.
* rs6000-tdep.c (set_powerpc_command, show_powerpc_command)
(_initialize_rs6000_tdep): Use add_basic_prefix_cmd,
add_show_prefix_cmd.
* riscv-tdep.c (show_riscv_command, set_riscv_command)
(show_debug_riscv_command, set_debug_riscv_command): Remove.
(_initialize_riscv_tdep): Use add_basic_prefix_cmd,
add_show_prefix_cmd.
* remote.c (remote_command, set_remote_cmd): Remove.
(_initialize_remote): Use add_basic_prefix_cmd.
* record-full.c (set_record_full_command)
(show_record_full_command): Remove.
(_initialize_record_full): Use add_basic_prefix_cmd,
add_show_prefix_cmd.
* record-btrace.c (cmd_set_record_btrace)
(cmd_show_record_btrace, cmd_set_record_btrace_bts)
(cmd_show_record_btrace_bts, cmd_set_record_btrace_pt)
(cmd_show_record_btrace_pt): Remove.
(_initialize_record_btrace): Use add_basic_prefix_cmd,
add_show_prefix_cmd.
* ravenscar-thread.c (set_ravenscar_command)
(show_ravenscar_command): Remove.
(_initialize_ravenscar): Use add_basic_prefix_cmd,
add_show_prefix_cmd.
* mips-tdep.c (show_mips_command, set_mips_command)
(_initialize_mips_tdep): Use add_basic_prefix_cmd,
add_show_prefix_cmd.
* maint.c (maintenance_command, maintenance_info_command)
(maintenance_check_command, maintenance_print_command)
(maintenance_set_cmd, maintenance_show_cmd): Remove.
(_initialize_maint_cmds): Use add_basic_prefix_cmd,
add_show_prefix_cmd.
(show_per_command_cmd): Remove.
* maint-test-settings.c (maintenance_set_test_settings_cmd):
Remove.
(maintenance_show_test_settings_cmd): Remove.
(_initialize_maint_test_settings): Use add_basic_prefix_cmd,
add_show_prefix_cmd.
* maint-test-options.c (maintenance_test_options_command):
Remove.
(_initialize_maint_test_options): Use add_basic_prefix_cmd.
* macrocmd.c (macro_command): Remove
(_initialize_macrocmd): Use add_basic_prefix_cmd.
* language.c (set_check, show_check): Remove.
(_initialize_language): Use add_basic_prefix_cmd,
add_show_prefix_cmd.
* infcmd.c (unset_command): Remove.
(_initialize_infcmd): Use add_basic_prefix_cmd.
* i386-tdep.c (set_mpx_cmd, show_mpx_cmd): Remove.
(_initialize_i386_tdep): Use add_basic_prefix_cmd,
add_show_prefix_cmd.
* go32-nat.c (go32_info_dos_command): Remove.
(_initialize_go32_nat): Use add_basic_prefix_cmd.
* cli/cli-decode.c (do_prefix_cmd, add_basic_prefix_cmd)
(do_show_prefix_cmd, add_show_prefix_cmd): New functions.
* frame.c (set_backtrace_cmd, show_backtrace_cmd): Remove.
(_initialize_frame): Use add_basic_prefix_cmd,
add_show_prefix_cmd.
* dcache.c (set_dcache_command, show_dcache_command): Remove.
(_initialize_dcache): Use add_basic_prefix_cmd,
add_show_prefix_cmd.
* cp-support.c (maint_cplus_command): Remove.
(_initialize_cp_support): Use add_basic_prefix_cmd.
* btrace.c (maint_btrace_cmd, maint_btrace_set_cmd)
(maint_btrace_show_cmd, maint_btrace_pt_set_cmd)
(maint_btrace_pt_show_cmd, _initialize_btrace): Use
add_basic_prefix_cmd, add_show_prefix_cmd.
* breakpoint.c (save_command): Remove.
(_initialize_breakpoint): Use add_basic_prefix_cmd.
* arm-tdep.c (set_arm_command, show_arm_command): Remove.
(_initialize_arm_tdep): Use add_basic_prefix_cmd,
add_show_prefix_cmd.
* ada-lang.c (maint_set_ada_cmd, maint_show_ada_cmd)
(set_ada_command, show_ada_command): Remove.
(_initialize_ada_language): Use add_basic_prefix_cmd,
add_show_prefix_cmd.
* command.h (add_basic_prefix_cmd, add_show_prefix_cmd): Declare.
gdb/testsuite/ChangeLog
2020-04-17 Tom Tromey <tromey@adacore.com>
* gdb.cp/maint.exp (test_help): Simplify multiple_help_body.
Update tests.
* gdb.btrace/cpu.exp: Update tests.
* gdb.base/maint.exp: Update tests.
* gdb.base/default.exp: Update tests.
* gdb.base/completion.exp: Update tests.
A few spots in gdb use sprintf_vma to print a CORE_ADDR. This will
fail on a 32-bit build once CORE_ADDR is always a 64-bit type.
This patch replaces these calls with phex instead.
gdb/ChangeLog
2020-03-12 Tom Tromey <tom@tromey.com>
* remote.c (remote_target::download_tracepoint)
(remote_target::enable_tracepoint)
(remote_target::disable_tracepoint): Use phex, not sprintf_vma.
* breakpoint.c (print_recreate_masked_watchpoint): Use phex, not
sprintf_vma.
New in v3:
- Code cleanups based on reviews.
New in v2:
- Fixed misc problems based on reviews.
- Switched to using gdbarch_program_breakpoint_here_p as opposed to
gdbarch_insn_is_breakpoint.
- Fixed matching of brk instructions. Previously the mask was incorrect, which
was showing up as a few failures in the testsuite. Now it is clean.
- New testcase (separate patch).
- Moved program_breakpoint_here () to arch-utils.c and made it the default
implementation of gdbarch_program_breakpoint_here_p.
--
It was reported to me that program breakpoints (permanent ones inserted into
the code itself) other than the one GDB uses for AArch64 (0xd4200000) do not
generate visible stops when continuing, and GDB will continue spinning
infinitely.
This happens because GDB, upon hitting one of those program breakpoints, thinks
the SIGTRAP came from a delayed breakpoint hit...
(gdb) x/i $pc
=> 0x4005c0 <problem_function>: brk #0x90f
(gdb) c
Continuing.
infrun: clear_proceed_status_thread (process 14198)
infrun: proceed (addr=0xffffffffffffffff, signal=GDB_SIGNAL_DEFAULT)
infrun: proceed: resuming process 14198
infrun: resume (step=0, signal=GDB_SIGNAL_0), trap_expected=0, current thread [process 14198] at 0x4005c0
infrun: infrun_async(1)
infrun: prepare_to_wait
infrun: target_wait (-1.0.0, status) =
infrun: 14198.14198.0 [process 14198],
infrun: status->kind = stopped, signal = GDB_SIGNAL_TRAP
infrun: handle_inferior_event status->kind = stopped, signal = GDB_SIGNAL_TRAP
infrun: stop_pc = 0x4005c0
infrun: delayed software breakpoint trap, ignoring
infrun: no stepping, continue
infrun: resume (step=0, signal=GDB_SIGNAL_0), trap_expected=0, current thread [process 14198] at 0x4005c0
infrun: prepare_to_wait
infrun: target_wait (-1.0.0, status) =
infrun: 14198.14198.0 [process 14198],
infrun: status->kind = stopped, signal = GDB_SIGNAL_TRAP
infrun: handle_inferior_event status->kind = stopped, signal = GDB_SIGNAL_TRAP
infrun: stop_pc = 0x4005c0
infrun: delayed software breakpoint trap, ignoring
infrun: no stepping, continue
infrun: resume (step=0, signal=GDB_SIGNAL_0), trap_expected=0, current thread [process 14198] at 0x4005c0
infrun: prepare_to_wait
infrun: target_wait (-1.0.0, status) =
infrun: 14198.14198.0 [process 14198],
infrun: status->kind = stopped, signal = GDB_SIGNAL_TRAP
infrun: handle_inferior_event status->kind = stopped, signal = GDB_SIGNAL_TRAP
infrun: stop_pc = 0x4005c0
infrun: delayed software breakpoint trap, ignoring
infrun: no stepping, continue
infrun: resume (step=0, signal=GDB_SIGNAL_0), trap_expected=0, current thread [process 14198] at 0x4005c0
infrun: prepare_to_wait
infrun: target_wait (-1.0.0, status) =
infrun: 14198.14198.0 [process 14198],
infrun: status->kind = stopped, signal = GDB_SIGNAL_TRAP
infrun: handle_inferior_event status->kind = stopped, signal = GDB_SIGNAL_TRAP
infrun: stop_pc = 0x4005c0
infrun: delayed software breakpoint trap, ignoring
infrun: no stepping, continue
infrun: resume (step=0, signal=GDB_SIGNAL_0), trap_expected=0, current thread [process 14198] at 0x4005c0
infrun: prepare_to_wait
infrun: target_wait (-1.0.0, status) =
infrun: 14198.14198.0 [process 14198],
infrun: status->kind = stopped, signal = GDB_SIGNAL_TRAP
...
... which is not the case.
If the program breakpoint is one GDB recognizes, then it will stop when it
hits it.
(gdb) x/i $pc
=> 0x4005c0 <problem_function>: brk #0x0
(gdb) c
Continuing.
infrun: clear_proceed_status_thread (process 14193)
infrun: proceed (addr=0xffffffffffffffff, signal=GDB_SIGNAL_DEFAULT)
infrun: proceed: resuming process 14193
infrun: resume (step=0, signal=GDB_SIGNAL_0), trap_expected=0, current thread [process 14193] at 0x4005c0
infrun: infrun_async(1)
infrun: prepare_to_wait
infrun: target_wait (-1.0.0, status) =
infrun: 14193.14193.0 [process 14193],
infrun: status->kind = stopped, signal = GDB_SIGNAL_TRAP
infrun: handle_inferior_event status->kind = stopped, signal = GDB_SIGNAL_TRAP
infrun: stop_pc = 0x4005c0
infrun: random signal (GDB_SIGNAL_TRAP)
infrun: stop_waiting
infrun: stop_all_threads
infrun: stop_all_threads, pass=0, iterations=0
infrun: process 14193 not executing
infrun: stop_all_threads, pass=1, iterations=1
infrun: process 14193 not executing
infrun: stop_all_threads done
Program received signal SIGTRAP, Trace/breakpoint trap.
problem_function () at brk_0.c:7
7 asm("brk %0\n\t" ::"n"(0x0));
infrun: infrun_async(0)
Otherwise GDB will keep trying to resume the inferior and will keep
seeing the SIGTRAP's, without stopping.
To the user it appears GDB has gone into an infinite loop, interruptible only
by Ctrl-C.
Also, windbg seems to use a different variation of AArch64 breakpoint compared
to GDB. This causes problems when debugging Windows on ARM binaries, when
program breakpoints are being used.
The proposed patch creates a new gdbarch method (gdbarch_program_breakpoint_here_p)
that tells GDB whether the underlying instruction is a breakpoint instruction
or not.
This is more general than only checking for the instruction GDB uses as
breakpoint.
The existing logic is still preserved for targets that do not implement this
new gdbarch method.
The end result is like so:
(gdb) x/i $pc
=> 0x4005c0 <problem_function>: brk #0x90f
(gdb) c
Continuing.
infrun: clear_proceed_status_thread (process 16417)
infrun: proceed (addr=0xffffffffffffffff, signal=GDB_SIGNAL_DEFAULT)
infrun: proceed: resuming process 16417
infrun: resume (step=0, signal=GDB_SIGNAL_0), trap_expected=0, current thread [process 16417] at 0x4005c0
infrun: infrun_async(1)
infrun: prepare_to_wait
infrun: target_wait (-1.0.0, status) =
infrun: 16417.16417.0 [process 16417],
infrun: status->kind = stopped, signal = GDB_SIGNAL_TRAP
infrun: handle_inferior_event status->kind = stopped, signal = GDB_SIGNAL_TRAP
infrun: stop_pc = 0x4005c0
infrun: random signal (GDB_SIGNAL_TRAP)
infrun: stop_waiting
infrun: stop_all_threads
infrun: stop_all_threads, pass=0, iterations=0
infrun: process 16417 not executing
infrun: stop_all_threads, pass=1, iterations=1
infrun: process 16417 not executing
infrun: stop_all_threads done
Program received signal SIGTRAP, Trace/breakpoint trap.
problem_function () at brk.c:7
7 asm("brk %0\n\t" ::"n"(0x900 + 0xf));
infrun: infrun_async(0)
gdb/ChangeLog:
2020-01-29 Luis Machado <luis.machado@linaro.org>
* aarch64-tdep.c (BRK_INSN_MASK): Define to 0xffe0001f.
(BRK_INSN_MASK): Define to 0xd4200000.
(aarch64_program_breakpoint_here_p): New function.
(aarch64_gdbarch_init): Set gdbarch_program_breakpoint_here_p hook.
* arch-utils.c (default_program_breakpoint_here_p): Moved from
breakpoint.c.
* arch-utils.h (default_program_breakpoint_here_p): Moved from
breakpoint.h
* breakpoint.c (bp_loc_is_permanent): Changed return type to bool and
call gdbarch_program_breakpoint_here_p.
(program_breakpoint_here): Moved to arch-utils.c, renamed to
default_program_breakpoint_here_p, changed return type to bool and
simplified.
* breakpoint.h (program_breakpoint_here): Moved prototype to
arch-utils.h, renamed to default_program_breakpoint_here_p and changed
return type to bool.
* gdbarch.c: Regenerate.
* gdbarch.h: Regenerate.
* gdbarch.sh (program_breakpoint_here_p): New method.
* infrun.c (handle_signal_stop): Call
gdbarch_program_breakpoint_here_p.
Marco Barisione