This is the mail archive of the gdb-patches@sources.redhat.com mailing list for the GDB project.


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]
Other format: [Raw text]

Re: [PATCH] -stack-select-frame



On Jun 16, 2005, at 4:05 PM, Nick Roberts wrote:


I thought it would save some time if the user doesn't need to see the
whole stack.

FWIW we've done a lot of careful timing analysis, and the back & forth communication between our GUI and gdb is so fast as to be pointless to optimize. We original considered adding special purpose "give Xcode everything it needs to know at a breakpoint hit" type commands but when we saw how fast the majority of MI commands can execute & be parsed by the GUI, it was obvious that this was not a useful area to optimize. And frankly, in my anecdotal experience, MacOS X isn't the fastest OS at things like "two processes talking over a pipe".


(one of the parts of this profiling which is especially useful is that we have a "mi-timings-enabled" setting. When it's enabled, every MI command reports how long gdb took to complete it, e.g. the "time=" bit at the end here:

-> 50-stack-list-frames 0 5
<- 50^done,stack=[frame= {level="0",addr="0x0009e7fc",fp="0xbfffe700",func=" [...] ,frame= {level="5",addr="0x936265d0",fp="0xbfffeee0",func="-[NSApplication run]"}],time= {wallclock="0.14353",user="0.00584",system="0.00335",start="1118952348.0 03847",end="1118952348.147372"}


we have similar timestamps put out by the GUI so when there's a slowdown we can establish where time was being spent.)


  enum mi_cmd_result
  mi_cmd_stack_select_frame (char *command, char **argv, int argc)
  {
-   if (!target_has_stack)
-     error (_("mi_cmd_stack_select_frame: No stack."));
-


Because now GDB will report it as follows:


-stack-select-frame
&"No stack.\n"
^error,msg="No stack."
(gdb)


You're right, currently it behaves like this:

-stack-select-frame
&"mi_cmd_stack_select_frame: No stack.\n"
^error,msg="mi_cmd_stack_select_frame: No stack."
(gdb)

but select_frame_command () will throw the error eventually, so there's no need to do the additional check here.


J



Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]