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Re: [RFAv2] Implement show | set may-call-functions [on|off]


On 4/26/19 10:34 PM, Philippe Waroquiers wrote:
> Inferior function calls are powerful but might lead to undesired
> results such as crashes when calling nested functions (frequently
> used in particular in Ada).
> 
> This implements a GDB setting to disable calling inferior functions.
> 
> Note: the idea is that if/when the 'slash command' patch is pushed,
> that this setting can be changed e.g. by using the shortcut /c.
> 
> This is version 2 of the patch.  It handles all the received comments,
> mostly replace 'can-call' by 'may-call', and avoid using
> 'inferior function call' in factor of 'calling function in the program'.
> 

Thanks.  I like this version a lot better.

Some nits below.  LGTM with those fixed.

>  
> +* New commands
> +
> +set may-call-functions [on|off]
> +show may-call-functions
> +  This controls whether GDB will attempt to call functions in
> +  the program, such as with expressions in print command.  It

"in print command" doesn't sound right to me.

Either "in print", or "in THE print command" would be good, I think.

> +  defaults to on.  Calling functions in the program being debugged
> +  can have undesired side effects.  It is now possible to forbid
> +  such function calls.  If function calls are forbidden, GDB will throw
> +  an error when a command (such as print an expression) calls a function

"such as printING an expression" ?  or (such as print EXPRESSION) if you
want to keep it short.

> +  in the program.
> +
>  *** Changes in GDB 8.3
>  
>  * GDB and GDBserver now support access to additional registers on
> diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
> index 0733e1acfd..2e4affd6c4 100644
> --- a/gdb/doc/gdb.texinfo
> +++ b/gdb/doc/gdb.texinfo
> @@ -18693,6 +18693,28 @@ the default C@t{++} exception handler and the inferior terminated.
>  Show the current setting of stack unwinding in the functions called by
>  @value{GDBN}.
>  
> +@item set may-call-functions
> +@kindex set may-call-functions
> +@cindex disabling calling functions in the program
> +@cindex calling functions in the program, disabling
> +Set permission to call functions in the program.
> +This controls whether @value{GDBN} will attempt to call functions in
> +the program, such as with expressions in @code{print}.  It

in the @code{print} command.

> +defaults to @code{on}.
> +
> +To call a function in the program, @value{GDBN} has to temporarily
> +modify the state of the inferior.  This has potentially undesired side
> +effects.  Also, having @value{GDBN} call nested functions is likely to
> +be erroneous and may even crash the program being debugged.  You can
> +avoid such hazards by forbidding @value{GDBN} from calling functions
> +in the program being debugged.  If calling functions in the program
> +are forbidden, 
s/are forbidden/is forbidden/

(calling functions ... is forbidden)

> GDB will throw an error when a command (such as print
> +an expression) starts a function call in the program.

"such as printING an expression" ?  

Or:

"such as print @var{expression}"
 
Thanks,
Pedro Alves


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