Emit and handle (custom) `-register-changed` notification
This commit adds new (custom) asynchronous notification about register value
being changed. Standard GDB does not notify MI clients about register value
being changed when debugging (for example, by CLI command `set $rax = 1` or
via Python's `Value.assign()`).
This caused libgdb's register value cache being out of sync. In the past,
this was partially worked around by manually emiting the notification on
`GDBRegisterWithValue` APIs, but this did not (and could not) handle the case
register was changed from GDB command line.
To solve this problem, this commit installs a custom Python event handler
that emits new GDB/MI notification - `-register-changed` - whenever a register
changes after debugee is stopped. This has been enabled by upstream GDB commit
4825fd "gdb/python: implement support for sending custom MI async notifications"
On libgdbs side, complete inferior state is invalidated. In theory, one could
carefully invalidate only the changed `GDBRegisterWithValue` but in certain cases
this could also change the backtrace (for example, if one updates stack pointer)
or position in code. So it seems safer to just invalidate everything.
"{ Encoding: utf8 }"
"
jv:libgdbs - GNU Debugger Interface Library
Copyright (C) 2015-now Jan Vrany
Copyright (C) 2022-2023 LabWare
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the 'Software'), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
"
"{ Package: 'jv:libgdbs' }"
"{ NameSpace: Smalltalk }"
GDBMICommand subclass:#GDBMI_var_set_visualizer
instanceVariableNames:''
classVariableNames:''
poolDictionaries:''
category:'GDB-Commands-MI'
!
!GDBMI_var_set_visualizer class methodsFor:'documentation'!
copyright
"
jv:libgdbs - GNU Debugger Interface Library
Copyright (C) 2015-now Jan Vrany
Copyright (C) 2022-2023 LabWare
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the 'Software'), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
"
!
documentation
"
Synopsis
-var-set-visualizer name visualizer
Set a visualizer for the variable object name.
visualizer is the visualizer to use. The special value ‘None’ means to disable any visualizer in use.
If not ‘None’, visualizer must be a Python expression. This expression must evaluate to a callable object which accepts a single argument. GDB will call this object with the value of the varobj name as an argument (this is done so that the same Python pretty-printing code can be used for both the CLI and MI). When called, this object must return an object which conforms to the pretty-printing interface (see Pretty Printing API).
The pre-defined function gdb.default_visualizer may be used to select a visualizer by following the built-in process (see Selecting Pretty-Printers). This is done automatically when a varobj is created, and so ordinarily is not needed.
This feature is only available if Python support is enabled. The MI command -list-features (see GDB/MI Support Commands) can be used to check this.
Example
Resetting the visualizer:
(gdb)
-var-set-visualizer V None
^done
Reselecting the default (type-based) visualizer:
(gdb)
-var-set-visualizer V gdb.default_visualizer
^done
Suppose SomeClass is a visualizer class. A lambda expression can be used to instantiate this class for a varobj:
(gdb)
-var-set-visualizer V 'lambda val: SomeClass()'
^done
"
! !
!GDBMI_var_set_visualizer methodsFor:'accessing'!
operation
^ 'var-set-visualizer'
! !
!GDBMI_var_set_visualizer class methodsFor:'documentation'!
version_HG
^ '$Changeset: <not expanded> $'
! !