This adds a few new subclasses of breakpoint. The inheritance
hierarchy is chosen to reflect what's already present in
initialize_breakpoint_ops -- it mirrors the way that the _ops
structures are filled in.
This patch also changes new_breakpoint_from_type to create the correct
sublcass based on bptype. This is important due to the somewhat
inverted way in which create_breakpoint works; and in particular later
patches will change some of these entries.
This converts watchpoints and masked watchpoints. to use
vtable_breakpoint_ops. For masked watchpoints, a new subclass must be
introduced, and watch_command_1 is changed to create one.
This adds methods to struct breakpoint. Each method has a similar
signature to a corresponding function in breakpoint_ops, with the
exceptions of create_sals_from_location and create_breakpoints_sal,
which can't be virtual methods on breakpoint -- they are only used
during the construction of breakpoints.
Then, this adds a new vtable_breakpoint_ops structure and populates it
with functions that simply forward a call from breakpoint_ops to the
corresponding virtual method. These are all done with lambdas,
because they are just a stepping stone -- by the end of the series,
this structure will be deleted.
This changes breakpoint_ops::print_one to return bool, and updates all
the implementations and the caller. The caller is changed so that a
NULL check is no longer needed -- something that will be impossible
with a real method.
This adds an assertion to clone_momentary_breakpoint. This will
eventually be removed, but in the meantime is is useful for helping
convince oneself that momentary breakpoints will always use
momentary_breakpoint_ops. This understanding will help when cleaning
up the code later.
The "catch load" code is reasonably self-contained, and so this patch
moves it out of breakpoint.c and into a new file, break-catch-load.c.
One function from breakpoint.c, print_solib_event, now has to be
exposed, but this seems pretty reasonable.
The clear command shouldn't delete momentary and internal breakpoints,
nor internal breakpoints created via Python's gdb.Breakpoint.
This patch fixes this issue and adds a testcase.
Regression tested on x86_64 openSUSE Tumbleweed(VERSION_ID="20220413").
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=7161
Add a getter and a setter for a minimal symbol's type. Remove the
corresponding macro and adjust all callers.
Change-Id: I89900df5ffa5687133fe1a16b2e0d4684e67a77d
Same idea as previous patch, but for symtab::objfile. I find
it clearer without this wrapper, as it shows that the objfile is
common to all symtabs of a given compunit. Otherwise, you could think
that each symtab (of a given compunit) can have a specific objfile.
Change-Id: Ifc0dbc7ec31a06eefa2787c921196949d5a6fcc6
Now that filtered and unfiltered output can be treated identically, we
can unify the printf family of functions. This is done under the name
"gdb_printf". Most of this patch was written by script.
Now that filtered and unfiltered output can be treated identically, we
can unify the putc family of functions. This is done under the name
"gdb_putc". Most of this patch was written by script.
If GDB reports a watchpoint hit, and then the next event is not
TARGET_WAITKIND_STOPPED, but instead some event for which there's a
catchpoint, such that GDB calls bpstat_stop_status, GDB mistakenly
thinks the watchpoint triggered. Vis, using foll-fork.c:
(gdb) awatch v
Hardware access (read/write) watchpoint 2: v
(gdb) catch fork
Catchpoint 3 (fork)
(gdb) c
Continuing.
Hardware access (read/write) watchpoint 2: v
Old value = 0
New value = 5
main () at gdb.base/foll-fork.c:16
16 pid = fork ();
(gdb)
Continuing.
Hardware access (read/write) watchpoint 2: v <<<<
<<<< these lines are spurious
Value = 5 <<<<
Catchpoint 3 (forked process 1712369), arch_fork (ctid=0x7ffff7fa4810) at arch-fork.h:49
49 arch-fork.h: No such file or directory.
(gdb)
The problem is that when we handle the fork event, nothing called
watchpoints_triggered before calling bpstat_stop_status. Thus, each
watchpoint's watchpoint_triggered field was still set to
watch_triggered_yes from the previous (real) watchpoint stop.
watchpoint_triggered is only current called in the handle_signal_stop
path, when handling TARGET_WAITKIND_STOPPED.
This fixes it by adding watchpoint_triggered calls in the other events
paths that call bpstat_stop_status. But instead of adding them
explicitly, it adds a new function bpstat_stop_status_nowatch that
wraps bpstat_stop_status and calls watchpoint_triggered, and then
replaces most calls to bpstat_stop_status with calls to
bpstat_stop_status_nowatch.
This required constifying watchpoints_triggered.
New test included, which fails without the fix.
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=28621
Change-Id: I282b38c2eee428d25319af3bc842f9feafed461c
This adds a constructor to bound_minimal_symbol, to avoid a build
failure with clang that Simon pointed out.
I also took the opportunity to remove some redundant initializations,
and to change one use of push_back to emplace_back, as suggested by
Simon.
While working on function calls, I realized that the thread_fsm member
of struct thread_info is a raw pointer to a resource it owns. This
commit changes the type of the thread_fsm member to a std::unique_ptr in
order to signify this ownership relationship and slightly ease resource
management (no need to manually call delete).
To ensure consistent use, the field is made a private member
(m_thread_fsm). The setter method (set_thread_fsm) can then check
that it is incorrect to associate a FSM to a thread_info object if
another one is already in place. This is ensured by an assertion.
The function run_inferior_call takes an argument as a pointer to a
call_thread_fsm and installs it in it in a thread_info instance. Also
change this function's signature to accept a unique_ptr in order to
signify that the ownership of the call_thread_fsm is transferred during
the call.
No user visible change expected after this commit.
Tested on x86_64-linux with no regression observed.
Change-Id: Ia1224f72a4afa247801ce6650ce82f90224a9ae8
Add a getter and a setter for a symtab's compunit_symtab. Remove the
corresponding macro and adjust all callers.
For brevity, I chose the name "compunit" instead of "compunit_symtab"
the the field, getter and setter names. Since we are already in symtab
context, the _symtab suffix seems redundant.
Change-Id: I4b9b731c96e3594f7733e75af1e3d01bc0e4fe92
I think it only really makes sense to call wrap_here with an argument
consisting solely of spaces. Given this, it seemed better to me that
the argument be an int, rather than a string. This patch is the
result. Much of it was written by a script.
In an earlier version of the pager rewrite series, it was important to
audit unfiltered output calls to see which were truly necessary.
This is no longer necessary, but it still seems like a decent cleanup
to change calls to avoid explicitly passing gdb_stdout. That is,
rather than using something like fprintf_unfiltered with gdb_stdout,
the code ought to use plain printf_unfiltered instead.
This patch makes this change. I went ahead and converted all the
_filtered calls I could find, as well, for the same clarity.
The "catch exec" code is reasonably self-contained, and so this patch
moves it out of breakpoint.c (the second largest source file in gdb)
and into a new file, break-catch-exec.c.
The "catch fork" code is reasonably self-contained, and so this patch
moves it out of breakpoint.c (the second largest source file in gdb)
and into a new file, break-catch-fork.c.
Many otherwise ordinary commands choose to use unfiltered output
rather than filtered. I don't think there's any reason for this, so
this changes many such commands to use filtered output instead.
Note that complete_command is not touched due to a comment there
explaining why unfiltered output is believed to be used.
This commit brings all the changes made by running gdb/copyright.py
as per GDB's Start of New Year Procedure.
For the avoidance of doubt, all changes in this commits were
performed by the script.
While working on target_waitstatus changes, I noticed a few places where
const target_waitstatus objects could be passed by reference instead of
by pointers. And in some cases, places where a target_waitstatus could
be passed as const, but was not. Convert them as much as possible.
Change-Id: Ied552d464be5d5b87489913b95f9720a5ad50c5a
The motivation is to reduce the number of places where unmanaged
pointers are returned from allocation type routines. All of the
callers are updated.
There should be no user visible changes after this commit.
This commit fixes Bug 28308, titled "Strange interactions with
dprintf and break/commands":
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=28308
Since creating that bug report, I've found a somewhat simpler way of
reproducing the problem. I've encapsulated it into the GDB test case
which I've created along with this bug fix. The name of the new test
is gdb.base/dprintf-execution-x-script.exp, I'll demonstrate the
problem using this test case, though for brevity, I've placed all
relevant files in the same directory and have renamed the files to all
start with 'dp-bug' instead of 'dprintf-execution-x-script'.
The script file, named dp-bug.gdb, consists of the following commands:
dprintf increment, "dprintf in increment(), vi=%d\n", vi
break inc_vi
commands
continue
end
run
Note that the final command in this script is 'run'. When 'run' is
instead issued interactively, the bug does not occur. So, let's look
at the interactive case first in order to see the correct/expected
output:
$ gdb -q -x dp-bug.gdb dp-bug
... eliding buggy output which I'll discuss later ...
(gdb) run
Starting program: /mesquite2/sourceware-git/f34-master/bld/gdb/tmp/dp-bug
vi=0
dprintf in increment(), vi=0
Breakpoint 2, inc_vi () at dprintf-execution-x-script.c:26
26 in dprintf-execution-x-script.c
vi=1
dprintf in increment(), vi=1
Breakpoint 2, inc_vi () at dprintf-execution-x-script.c:26
26 in dprintf-execution-x-script.c
vi=2
dprintf in increment(), vi=2
Breakpoint 2, inc_vi () at dprintf-execution-x-script.c:26
26 in dprintf-execution-x-script.c
vi=3
[Inferior 1 (process 1539210) exited normally]
In this run, in which 'run' was issued from the gdb prompt (instead
of at the end of the script), there are three dprintf messages along
with three 'Breakpoint 2' messages. This is the correct output.
Now let's look at the output that I snipped above; this is the output
when 'run' is issued from the script loaded via GDB's -x switch:
$ gdb -q -x dp-bug.gdb dp-bug
Reading symbols from dp-bug...
Dprintf 1 at 0x40116e: file dprintf-execution-x-script.c, line 38.
Breakpoint 2 at 0x40113a: file dprintf-execution-x-script.c, line 26.
vi=0
dprintf in increment(), vi=0
Breakpoint 2, inc_vi () at dprintf-execution-x-script.c:26
26 dprintf-execution-x-script.c: No such file or directory.
vi=1
Breakpoint 2, inc_vi () at dprintf-execution-x-script.c:26
26 in dprintf-execution-x-script.c
vi=2
Breakpoint 2, inc_vi () at dprintf-execution-x-script.c:26
26 in dprintf-execution-x-script.c
vi=3
[Inferior 1 (process 1539175) exited normally]
In the output shown above, only the first dprintf message is printed.
The 2nd and 3rd dprintf messages are missing! However, all three
'Breakpoint 2...' messages are still printed.
Why does this happen?
bpstat_do_actions_1() in gdb/breakpoint.c contains the following
comment and code near the start of the function:
/* Avoid endless recursion if a `source' command is contained
in bs->commands. */
if (executing_breakpoint_commands)
return 0;
scoped_restore save_executing
= make_scoped_restore (&executing_breakpoint_commands, 1);
Also, as described by this comment prior to the 'async' field
in 'struct ui' in top.h, the main UI starts off in sync mode
when processing command line arguments:
/* True if the UI is in async mode, false if in sync mode. If in
sync mode, a synchronous execution command (e.g, "next") does not
return until the command is finished. If in async mode, then
running a synchronous command returns right after resuming the
target. Waiting for the command's completion is later done on
the top event loop. For the main UI, this starts out disabled,
until all the explicit command line arguments (e.g., `gdb -ex
"start" -ex "next"') are processed. */
This combination of things, the state of the static global
'executing_breakpoint_commands' plus the state of the async
field in the main UI causes this behavior.
This is a backtrace after hitting the dprintf breakpoint for
the second time when doing 'run' from the script file, i.e.
non-interactively:
Thread 1 "gdb" hit Breakpoint 3, bpstat_do_actions_1 (bsp=0x7fffffffc2b8)
at /ironwood1/sourceware-git/f34-master/bld/../../worktree-master/gdb/breakpoint.c:4431
4431 if (executing_breakpoint_commands)
#0 bpstat_do_actions_1 (bsp=0x7fffffffc2b8)
at gdb/breakpoint.c:4431
#1 0x00000000004d8bc6 in dprintf_after_condition_true (bs=0x1538090)
at gdb/breakpoint.c:13048
#2 0x00000000004c5caa in bpstat_stop_status (aspace=0x116dbc0, bp_addr=0x40116e, thread=0x137f450, ws=0x7fffffffc718,
stop_chain=0x1538090) at gdb/breakpoint.c:5498
#3 0x0000000000768d98 in handle_signal_stop (ecs=0x7fffffffc6f0)
at gdb/infrun.c:6172
#4 0x00000000007678d3 in handle_inferior_event (ecs=0x7fffffffc6f0)
at gdb/infrun.c:5662
#5 0x0000000000763cd5 in fetch_inferior_event ()
at gdb/infrun.c:4060
#6 0x0000000000746d7d in inferior_event_handler (event_type=INF_REG_EVENT)
at gdb/inf-loop.c:41
#7 0x00000000007a702f in handle_target_event (error=0, client_data=0x0)
at gdb/linux-nat.c:4207
#8 0x0000000000b8cd6e in gdb_wait_for_event (block=block@entry=0)
at gdbsupport/event-loop.cc:701
#9 0x0000000000b8d032 in gdb_wait_for_event (block=0)
at gdbsupport/event-loop.cc:597
#10 gdb_do_one_event () at gdbsupport/event-loop.cc:212
#11 0x00000000009d19b6 in wait_sync_command_done ()
at gdb/top.c:528
#12 0x00000000009d1a3f in maybe_wait_sync_command_done (was_sync=0)
at gdb/top.c:545
#13 0x00000000009d2033 in execute_command (p=0x7fffffffcb18 "", from_tty=0)
at gdb/top.c:676
#14 0x0000000000560d5b in execute_control_command_1 (cmd=0x13b9bb0, from_tty=0)
at gdb/cli/cli-script.c:547
#15 0x000000000056134a in execute_control_command (cmd=0x13b9bb0, from_tty=0)
at gdb/cli/cli-script.c:717
#16 0x00000000004c3bbe in bpstat_do_actions_1 (bsp=0x137f530)
at gdb/breakpoint.c:4469
#17 0x00000000004c3d40 in bpstat_do_actions ()
at gdb/breakpoint.c:4533
#18 0x00000000006a473a in command_handler (command=0x1399ad0 "run")
at gdb/event-top.c:624
#19 0x00000000009d182e in read_command_file (stream=0x113e540)
at gdb/top.c:443
#20 0x0000000000563697 in script_from_file (stream=0x113e540, file=0x13bb0b0 "dp-bug.gdb")
at gdb/cli/cli-script.c:1642
#21 0x00000000006abd63 in source_gdb_script (extlang=0xc44e80 <extension_language_gdb>, stream=0x113e540,
file=0x13bb0b0 "dp-bug.gdb") at gdb/extension.c:188
#22 0x0000000000544400 in source_script_from_stream (stream=0x113e540, file=0x7fffffffd91a "dp-bug.gdb",
file_to_open=0x13bb0b0 "dp-bug.gdb")
at gdb/cli/cli-cmds.c:692
#23 0x0000000000544557 in source_script_with_search (file=0x7fffffffd91a "dp-bug.gdb", from_tty=1, search_path=0)
at gdb/cli/cli-cmds.c:750
#24 0x00000000005445cf in source_script (file=0x7fffffffd91a "dp-bug.gdb", from_tty=1)
at gdb/cli/cli-cmds.c:759
#25 0x00000000007cf6d9 in catch_command_errors (command=0x5445aa <source_script(char const*, int)>,
arg=0x7fffffffd91a "dp-bug.gdb", from_tty=1, do_bp_actions=false)
at gdb/main.c:523
#26 0x00000000007cf85d in execute_cmdargs (cmdarg_vec=0x7fffffffd1b0, file_type=CMDARG_FILE, cmd_type=CMDARG_COMMAND,
ret=0x7fffffffd18c) at gdb/main.c:615
#27 0x00000000007d0c8e in captured_main_1 (context=0x7fffffffd3f0)
at gdb/main.c:1322
#28 0x00000000007d0eba in captured_main (data=0x7fffffffd3f0)
at gdb/main.c:1343
#29 0x00000000007d0f25 in gdb_main (args=0x7fffffffd3f0)
at gdb/main.c:1368
#30 0x00000000004186dd in main (argc=5, argv=0x7fffffffd508)
at gdb/gdb.c:32
There are two frames for bpstat_do_actions_1(), one at frame #16 and
the other at frame #0. The one at frame #16 is processing the actions
for Breakpoint 2, which is a 'continue'. The one at frame #0 is attempting
to process the dprintf breakpoint action. However, at this point,
the value of 'executing_breakpoint_commands' is 1, forcing an early
return, i.e. prior to executing the command(s) associated with the dprintf
breakpoint.
For the sake of comparison, this is what the stack looks like when hitting
the dprintf breakpoint for the second time when issuing the 'run'
command from the GDB prompt.
Thread 1 "gdb" hit Breakpoint 3, bpstat_do_actions_1 (bsp=0x7fffffffccd8)
at /ironwood1/sourceware-git/f34-master/bld/../../worktree-master/gdb/breakpoint.c:4431
4431 if (executing_breakpoint_commands)
#0 bpstat_do_actions_1 (bsp=0x7fffffffccd8)
at gdb/breakpoint.c:4431
#1 0x00000000004d8bc6 in dprintf_after_condition_true (bs=0x16b0290)
at gdb/breakpoint.c:13048
#2 0x00000000004c5caa in bpstat_stop_status (aspace=0x116dbc0, bp_addr=0x40116e, thread=0x13f0e60, ws=0x7fffffffd138,
stop_chain=0x16b0290) at gdb/breakpoint.c:5498
#3 0x0000000000768d98 in handle_signal_stop (ecs=0x7fffffffd110)
at gdb/infrun.c:6172
#4 0x00000000007678d3 in handle_inferior_event (ecs=0x7fffffffd110)
at gdb/infrun.c:5662
#5 0x0000000000763cd5 in fetch_inferior_event ()
at gdb/infrun.c:4060
#6 0x0000000000746d7d in inferior_event_handler (event_type=INF_REG_EVENT)
at gdb/inf-loop.c:41
#7 0x00000000007a702f in handle_target_event (error=0, client_data=0x0)
at gdb/linux-nat.c:4207
#8 0x0000000000b8cd6e in gdb_wait_for_event (block=block@entry=0)
at gdbsupport/event-loop.cc:701
#9 0x0000000000b8d032 in gdb_wait_for_event (block=0)
at gdbsupport/event-loop.cc:597
#10 gdb_do_one_event () at gdbsupport/event-loop.cc:212
#11 0x00000000007cf512 in start_event_loop ()
at gdb/main.c:421
#12 0x00000000007cf631 in captured_command_loop ()
at gdb/main.c:481
#13 0x00000000007d0ebf in captured_main (data=0x7fffffffd3f0)
at gdb/main.c:1353
#14 0x00000000007d0f25 in gdb_main (args=0x7fffffffd3f0)
at gdb/main.c:1368
#15 0x00000000004186dd in main (argc=5, argv=0x7fffffffd508)
at gdb/gdb.c:32
This relatively short backtrace is due to the current UI's async field
being set to 1.
Yet another thing to be aware of regarding this problem is the
difference in the way that commands associated to dprintf breakpoints
versus regular breakpoints are handled. While they both use a command
list associated with the breakpoint, regular breakpoints will place
the commands to be run on the bpstat chain constructed in
bp_stop_status(). These commands are run later on. For dprintf
breakpoints, commands are run via the 'after_condition_true' function
pointer directly from bpstat_stop_status(). (The 'commands' field in
the bpstat is cleared in dprintf_after_condition_true(). This
prevents the dprintf commands from being run again later on when other
commands on the bpstat chain are processed.)
Another thing that I noticed is that dprintf breakpoints are the only
type of breakpoint which use 'after_condition_true'. This suggests
that one possible way of fixing this problem, that of making dprintf
breakpoints work more like regular breakpoints, probably won't work.
(I must admit, however, that my understanding of this code isn't
complete enough to say why. I'll trust that whoever implemented it
had a good reason for doing it this way.)
The comment referenced earlier regarding 'executing_breakpoint_commands'
states that the reason for checking this variable is to avoid
potential endless recursion when a 'source' command appears in
bs->commands. We know that a dprintf command is constrained to either
1) execution of a GDB printf command, 2) an inferior function call of
a printf-like function, or 3) execution of an agent-printf command.
Therefore, infinite recursion due to a 'source' command cannot happen
when executing commands upon hitting a dprintf breakpoint.
I chose to fix this problem by having dprintf_after_condition_true()
directly call execute_control_commands(). This means that it no
longer attempts to go through bpstat_do_actions_1() avoiding the
infinite recursion check for potential 'source' commands on the
command chain. I think it simplifies this code a little bit too, a
definite bonus.
Summary:
* breakpoint.c (dprintf_after_condition_true): Don't call
bpstat_do_actions_1(). Call execute_control_commands()
instead.
I don't find that the bpstat typedef, which hides a pointer, is
particularly useful. In fact, it confused me many times, and I just see
it as something to remember that adds cognitive load. Also, with C++,
we might want to be able to pass bpstats objects by const-reference, not
necessarily by pointer.
So, remove the bpstat typedef and rename struct bpstats to bpstat (since
it represents one bpstat, it makes sense that it is singular).
Change-Id: I52e763b6e54ee666a9e045785f686d37b4f5f849
There's a common pattern to call add_basic_prefix_cmd and
add_show_prefix_cmd to add matching set and show commands. Add the
add_setshow_prefix_cmd function to factor that out and use it at a few
places.
Change-Id: I6e9e90a30e9efb7b255bf839cac27b85d7069cfd
The bug fixed by this [1] patch was caused by an out-of-bounds access to
a value's content. The code gets the value's content (just a pointer)
and then indexes it with a non-sensical index.
This made me think of changing functions that return value contents to
return array_views instead of a plain pointer. This has the advantage
that when GDB is built with _GLIBCXX_DEBUG, accesses to the array_view
are checked, making bugs more apparent / easier to find.
This patch changes the return types of these functions, and updates
callers to call .data() on the result, meaning it's not changing
anything in practice. Additional work will be needed (which can be done
little by little) to make callers propagate the use of array_view and
reap the benefits.
[1] https://sourceware.org/pipermail/gdb-patches/2021-September/182306.html
Change-Id: I5151f888f169e1c36abe2cbc57620110673816f3
I stumbled on a bug caused by the fact that a code path read
target_waitstatus::value::sig (expecting it to contain a gdb_signal
value) while target_waitstatus::kind was TARGET_WAITKIND_FORKED. This
meant that the active union field was in fact
target_waitstatus::value::related_pid, and contained a ptid. The read
signal value was therefore garbage, and that caused GDB to crash soon
after. Or, since that GDB was built with ubsan, this nice error
message:
/home/simark/src/binutils-gdb/gdb/linux-nat.c:1271:12: runtime error: load of value 2686365, which is not a valid value for type 'gdb_signal'
Despite being a large-ish change, I think it would be nice to make
target_waitstatus safe against that kind of bug. As already done
elsewhere (e.g. dynamic_prop), validate that the type of value read from
the union matches what is supposed to be the active field.
- Make the kind and value of target_waitstatus private.
- Make the kind initialized to TARGET_WAITKIND_IGNORE on
target_waitstatus construction. This is what most users appear to do
explicitly.
- Add setters, one for each kind. Each setter takes as a parameter the
data associated to that kind, if any. This makes it impossible to
forget to attach the associated data.
- Add getters, one for each associated data type. Each getter
validates that the data type fetched by the user matches the wait
status kind.
- Change "integer" to "exit_status", "related_pid" to "child_ptid",
just because that's more precise terminology.
- Fix all users.
That last point is semi-mechanical. There are a lot of obvious changes,
but some less obvious ones. For example, it's not possible to set the
kind at some point and the associated data later, as some users did.
But in any case, the intent of the code should not change in this patch.
This was tested on x86-64 Linux (unix, native-gdbserver and
native-extended-gdbserver boards). It was built-tested on x86-64
FreeBSD, NetBSD, MinGW and macOS. The rest of the changes to native
files was done as a best effort. If I forgot any place to update in
these files, it should be easy to fix (unless the change happens to
reveal an actual bug).
Change-Id: I0ae967df1ff6e28de78abbe3ac9b4b2ff4ad03b7
String-like settings (var_string, var_filename, var_optional_filename,
var_string_noescape) currently take a pointer to a `char *` storage
variable (typically global) that holds the setting's value. I'd like to
"mordernize" this by changing them to use an std::string for storage.
An obvious reason is that string operations on std::string are often
easier to write than with C strings. And they avoid having to do any
manual memory management.
Another interesting reason is that, with `char *`, nullptr and an empty
string often both have the same meaning of "no value". String settings
are initially nullptr (unless initialized otherwise). But when doing
"set foo" (where `foo` is a string setting), the setting now points to
an empty string. For example, solib_search_path is nullptr at startup,
but points to an empty string after doing "set solib-search-path". This
leads to some code that needs to check for both to check for "no value".
Or some code that converts back and forth between NULL and "" when
getting or setting the value. I find this very error-prone, because it
is very easy to forget one or the other. With std::string, we at least
know that the variable is not "NULL". There is only one way of
representing an empty string setting, that is with an empty string.
I was wondering whether the distinction between NULL and "" would be
important for some setting, but it doesn't seem so. If that ever
happens, it would be more C++-y and self-descriptive to use
optional<string> anyway.
Actually, there's one spot where this distinction mattered, it's in
init_history, for the test gdb.base/gdbinit-history.exp. init_history
sets the history filename to the default ".gdb_history" if it sees that
the setting was never set - if history_filename is nullptr. If
history_filename is an empty string, it means the setting was explicitly
cleared, so it leaves it as-is. With the change to std::string, this
distinction doesn't exist anymore. This can be fixed by moving the code
that chooses a good default value for history_filename to
_initialize_top. This is ran before -ex commands are processed, so an
-ex command can then clear that value if needed (what
gdb.base/gdbinit-history.exp tests).
Another small improvement, in my opinion is that we can now easily
give string parameters initial values, by simply initializing the global
variables, instead of xstrdup-ing it in the _initialize function.
In Python and Guile, when registering a string-like parameter, we
allocate (with new) an std::string that is owned by the param_smob (in
Guile) and the parmpy_object (in Python) objects.
This patch started by changing all relevant add_setshow_* commands to
take an `std::string *` instead of a `char **` and fixing everything
that failed to build. That includes of course all string setting
variable and their uses.
string_option_def now uses an std::string also, because there's a
connection between options and settings (see
add_setshow_cmds_for_options).
The add_path function in source.c is really complex and twisted, I'd
rather not try to change it to work on an std::string right now.
Instead, I added an overload that copies the std:string to a `char *`
and back. This means more copying, but this is not used in a hot path
at all, so I think it is acceptable.
Change-Id: I92c50a1bdd8307141cdbacb388248e4e4fc08c93
Co-authored-by: Lancelot SIX <lsix@lancelotsix.com>
This started out as changing thread_info::name to a unique_xmalloc_ptr.
That showed that almost all users of that field had the same logic to
get a thread's name: use thread_info::name if non-nullptr, else ask the
target. Factor out this logic in a new thread_name free function. Make
the field private (rename to m_name) and add some accessors.
Change-Id: Iebdd95f4cd21fbefc505249bd1d05befc466a2fc
Rename thread_info::executing to thread_info::m_executing, and make it
private. Add a new get/set member functions, and convert GDB to make
use of these.
The only real change of interest in this patch is in thread.c where I
have deleted the helper function set_executing_thread, and now just
use the new set function thread_info::set_executing. However, the old
helper function set_executing_thread included some code to reset the
thread's stop_pc, so I moved this code into the new function
thread_info::set_executing. However, I don't believe there is
anywhere that this results in a change of behaviour, previously the
executing flag was always set true through a call to
set_executing_thread anyway.
Remove breakpoint_find_if, replace its sole usage with using
all_breakpoints directly instead. At the same time, change return
types to use bool.
Change-Id: I9ec392236b4804b362d16ab563330b9c07311106
