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author | Pedro Alves <palves@redhat.com> | 2019-07-03 13:34:20 +0100 |
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committer | Pedro Alves <palves@redhat.com> | 2019-07-03 13:35:45 +0100 |
commit | fdbc98707b0ab48fd8ca3ac37acefa120496baf6 (patch) | |
tree | 5894a73e3e58bcd087918752ce0e0790ec4c14bf /gdb/stubs | |
parent | c6ac893109fdc2c3fce2b7457adccdc10f235354 (diff) | |
download | gdb-fdbc98707b0ab48fd8ca3ac37acefa120496baf6.zip gdb-fdbc98707b0ab48fd8ca3ac37acefa120496baf6.tar.gz gdb-fdbc98707b0ab48fd8ca3ac37acefa120496baf6.tar.bz2 |
Introduce the "with" command
( See original discussion and prototype here:
https://sourceware.org/ml/gdb-patches/2019-05/msg00570.html )
(gdb) help with
Temporarily set SETTING to VALUE, run COMMAND, and restore SETTING.
Usage: with SETTING [VALUE] [-- COMMAND]
Usage: w SETTING [VALUE] [-- COMMAND]
With no COMMAND, repeats the last executed command.
SETTING is any setting you can change with the "set" subcommands.
E.g.:
with language pascal -- print obj
with print elements unlimited -- print obj
As can be seen above, the "with" command is just like "set", but
instead of setting the setting permanently, it sets the setting, runs
a command and then restores the setting.
(gdb) p g_s
$1 = {a = 1, b = 2, c = 3}
(gdb) with language ada -- print g_s
$2 = (a => 1, b => 2, c => 3)
Warning: the current language does not match this frame.
(gdb) show language
The current source language is "auto; currently c".
(gdb) with print elements 100 -- with print object on -- print 1
$3 = 1
You can shorten things a bit though, as long as unambiguous. So this:
(gdb) with print elements 100 -- with print object off -- print 1
is the same as:
(gdb) w p el 100 -- w p o 0 -- p 1
Note that the patch adds a "w" alias for "with", as "w" is not
currently taken:
(gdb) w
Ambiguous command "w": watch, wh, whatis, where, while, while-stepping, winheight, ws.
Let me know if you'd prefer to reserve "w" for one of the other
commands above. IMHO, this command will end up being used frequently
enough that it deserves the "w" shorthand.
A nice feature is that this is fully integrated with TAB-completion:
(gdb) with p[TAB]
pagination print prompt python
(gdb) with print [TAB]
address max-depth static-members
array max-symbolic-offset symbol
array-indexes null-stop symbol-filename
asm-demangle object symbol-loading
demangle pascal_static-members thread-events
elements pretty type
entry-values raw union
frame-arguments repeats vtbl
inferior-events sevenbit-strings
(gdb) with print [TAB]
(gdb) with print elements unlimited -- thread apply all -[TAB]
-ascending -c -q -s
(gdb) with print elements unlimited -- print -[TAB]
-address -max-depth -repeats -vtbl
-array -null-stop -static-members
-array-indexes -object -symbol
-elements -pretty -union
The main advantage of this new command compared to command options,
like the new "print -OPT", is that this command works with any
setting, and, it works nicely when you want to override a setting
while running a user-defined command, like:
(gdb) with print pretty -- usercmd
The disadvantage is that it isn't as compact or easy to type. I think
of command options and this command as complementary. I think that
even with this new command, it makes sense to continue developing the
command options in the direction of exposing most-oft-used settings as
command options.
Inspired by Philippe's "/" command proposal, if no command is
specified, then the last command is re-invoked, under the overridden
setting:
(gdb) p g_s
$1 = {a = 1, b = 2, c = 3}
(gdb) with language ada
$2 = (a => 1, b => 2, c => 3)
Warning: the current language does not match this frame.
Note: "with" requires "--" to separate the setting from the command.
It might be possible to do without that, but, I haven't tried it yet,
and I think that this can go in without it. We can always downgrade
to making "--" optional if we manage to make it work.
On to the patch itself, the implementation of the command is simpler
than one might expect. A few details:
- I factored out a bit from pipe_command into repeat_previous
directly, because otherwise I'd need to copy&paste the same code and
same error message in the with command.
- The parse_cli_var_uinteger / parse_cli_var_zuinteger_unlimited /
do_set_command changes are necessary since we can now pass an empty
string as argument.
- do_show_command was split in two, as a FIXME comment suggests, but
for a different reason: we need to get a string version of a "set"
command's value, and we already had code for that in
do_show_command. That code is now factored out to the new
get_setshow_command_value_string function.
- There's a new "maint with" command added too:
(gdb) help maint with
Like "with", but works with "maintenance set" variables.
Usage: maintenance with SETTING [VALUE] [-- COMMAND]
With no COMMAND, repeats the last executed command.
SETTING is any setting you can change with the "maintenance set"
subcommands.
"with" and "maint with" share 99% of the implementation.
This might be useful on its own, but it's also useful for testing,
since with this, we can use the "maint set/show test-settings"
settings for exercising the "with" machinery with all the command
type variants (all enum var_types). This is done in the new
gdb/base/with.exp testcase.
The documentation bits are originally based on Philippe's docs for the
"/" command, hence the attribution in the ChangeLog.
gdb/ChangeLog:
2019-07-03 Pedro Alves <palves@redhat.com>
* NEWS (New commands): Mention "with" and "maint with".
* cli/cli-cmds.c (with_command_1, with_command_completer_1)
(with_command, with_command_completer): New.
(pipe_command): Adjust to new repeat_previous
interface.
(_initialize_cli_cmds): Install the "with" command and its "w"
alias.
* cli/cli-cmds.h (with_command_1, with_command_completer_1): New
declarations.
* cli/cli-setshow.c (parse_cli_var_uinteger)
(parse_cli_var_zuinteger_unlimited, do_set_command): Handle empty
argument strings for all var_types.
(get_setshow_command_value_string): New, factored out from ...
(do_show_command): ... this.
* cli/cli-setshow.h: Include <string>.
(get_setshow_command_value_string): Declare.
* command.h (repeat_previous): Now returns const char *. Adjust
comment.
* maint.c: Include "cli/cli-cmds.h".
(maintenance_with_cmd, maintenance_with_cmd_completer): New.
(_initialize_maint_cmds): Register the "maintenance with" command.
* top.c (repeat_previous): Move bits from pipe_command here:
Return the saved command line, if any; error out if there's no
command to relaunch.
gdb/doc/ChangeLog:
2019-07-03 Pedro Alves <palves@redhat.com>
Philippe Waroquiers <philippe.waroquiers@skynet.be>
* gdb.texinfo (Command Settings): New node documenting the general
concept of settings, how to change them, and the new "with"
command.
(Maintenance Commands): Document "maint with".
gdb/testsuite/ChangeLog:
2019-07-03 Pedro Alves <palves@redhat.com>
* gdb.base/with.c: New file.
* gdb.base/with.exp: New file.
Diffstat (limited to 'gdb/stubs')
0 files changed, 0 insertions, 0 deletions