[lldb-dev] Watching the current frame locals
Eran Ifrah
eran.ifrah at gmail.com
Tue Apr 8 12:35:37 PDT 2014
Thanks for the tip. It works fine for 'string' types
But for simple types (e.g. 'int') GetSummary() returns an empty string.. :/
So I ended up writing this little method:
http://pastebin.com/pj0znv9j
Which seems to work fine for me (ofcourse, I will know more when I upload
the pre-release to my testers)
Thanks
On Tue, Apr 8, 2014 at 9:04 PM, <jingham at apple.com> wrote:
> That is what the Summary is for. The Summary, if it exists, is the
> preferred "interpreted" presentation of the data held by the SBValue. So
> for a char *, the Value is the pointer value, but the Summary is the
> c-string contents.
>
> Jim
>
> On Apr 8, 2014, at 10:57 AM, Eran Ifrah <eran.ifrah at gmail.com> wrote:
>
> > Hello Enrico / All,
> >
> > I debugged it and it seems like a bug in my code.
> > To get the frame locals (function args and locals) I was using this call:
> >
> > frame.GetBlock().GetVariables()
> >
> > While I should have simply call to frame.GetVariables()
> > Which fixes the problem.
> >
> > However, I am facing another issue:
> > It seems like the function "const char* SBValue::GetValue()" returns the
> pointer address as string instead of the actual content
> >
> > Any quick way to get the data as an actual c-str?
> >
> > For example:
> >
> > int main(int argc, char** argv) {
> > return 0;
> > }
> >
> > My lldb UI for the "locals" view looks like this (best viewed in
> monospace font ;)) :
> >
> >
> --------------------------------------------------------------------------------
> > name | type | value
> >
> --------------------------------------------------------------------------------
> > argc | int | 1
> > argv | const char** | 0xfffffab123 (some random address)
> > | | |
> > +-*argv | const char* | 0xfffffab124 (some other address)
> > | | |
> > +- **argv| char | '/'
> >
> > In the code, I can identify that *argv is of type lldb::eBasicType*Char,
> however, I can't find a way to extract the string itself (it should be
> "/home/eran/test/TestLLDB")
> >
> > Any hints?
> >
> > Thanks!
> >
> >
> >
> >
> > On Mon, Apr 7, 2014 at 5:31 AM, Eran Ifrah <eran.ifrah at gmail.com> wrote:
> > Thanks, will debug this and see where it fails
> >
> > Eran
> >
> >
> > On Mon, Apr 7, 2014 at 1:43 AM, Enrico Granata <egranata at apple.com>
> wrote:
> > Yeah the const char* definitely should have a value.
> > I am guessing the variable is in scope all right. Does it have a summary
> if you ask for that?
> > Does the same API call work if you stop directly within LLDB and use the
> Python API?
> > More context (e.g. a repro case) would also help - or maybe if you can
> step through the LLDB code and see where we fail. If these are just frame
> locals I expect the relevant code to be in ValueObject.cpp GetValueAsCString
> >
> > Sent from the iPhone of
> > Enrico Granata <egranata@🍎.com>
> >
> > On Apr 6, 2014, at 12:26 PM, Eran Ifrah <eran.ifrah at gmail.com> wrote:
> >
> >> One of the local variables was 'const char*' so I would expect it to
> have a value and others were of type of 'wxString'
> >> In the UI I expanded all the way to the _M_data which is of type
> 'wchar_t*' - and still nothing
> >>
> >> Eran
> >>
> >>
> >>
> >> On Sun, Apr 6, 2014 at 9:13 PM, Enrico Granata <egranata at apple.com>
> wrote:
> >> What is the data type of your variables?
> >>
> >> If they are aggregate types (structs, classes, ...) they won't have a
> value.
> >>
> >> Only basic types (int, float, char, ..., you get the idea - and
> pointers) have a value.
> >>
> >> For other types, they might have a summary, or they might have
> children, but definitely no value.
> >>
> >> Sent from the iPhone of
> >> Enrico Granata <egranata@🍎.com>
> >>
> >> On Apr 6, 2014, at 7:02 AM, Eran Ifrah <eran.ifrah at gmail.com> wrote:
> >>
> >>> Hello all,
> >>>
> >>> I am at a phase where I want to display the current frame local
> variables whenever the debugger "stops"
> >>> I was able to get a list of the selected frame's variables in the
> following manner:
> >>>
> >>> lldb::SBFrame frame =
> m_target.GetProcess().GetSelectedThread().GetSelectedFrame();
> >>> ...
> >>> lldb::SBValueList args = frame.GetBlock().GetVariables(m_target, true,
> true, false);
> >>> for(size_t i=0; i<args.GetSize(); ++i) {
> >>> lldb::SBValue value = args.GetValueAtIndex(i);
> >>> if ( value.IsValid() ) {
> >>> LLDBLocalVariable::Ptr_t var( new LLDBLocalVariable(value)
> );
> >>> locals.push_back( var );
> >>> }
> >>> }
> >>>
> >>> Now, LLDBLocalVariable is a thin wrapper class for UI purposes.
> >>> What it does is basically copies values from lldb::SBValue:
> >>>
> >>> LLDBLocalVariable::LLDBLocalVariable(lldb::SBValue value) {
> >>> SetName( value.GetName() );
> >>> SetType( value.GetTypeName() );
> >>> SetValue( value.GetValue() ); // always returns null
> >>> ... // code that handles children of value
> >>> }
> >>>
> >>> value.GetName() and value.GetTypeName() are working as expected (i.e.
> I get the correct type name and its name)
> >>> However, I can't get the value as "string". I was naive enough to
> think that const char* SBValue::GetValue() will do the trick... but this
> always returns NULL.
> >>>
> >>> Any suggestions on what am I doing wrong? an example on how to extract
> the variable's value in string format will be really appreciated
> >>>
> >>> Thanks,
> >>>
> >>> P.S.
> >>> This is Linux 13.10 / 64 bit
> >>> Self compiled lldb
> >>>
> >>> --
> >>> Eran Ifrah
> >>> Author of codelite, a cross platform open source C/C++ IDE:
> http://www.codelite.org
> >>> wxCrafter, a wxWidgets RAD: http://wxcrafter.codelite.org
> >>> _______________________________________________
> >>> lldb-dev mailing list
> >>> lldb-dev at cs.uiuc.edu
> >>> http://lists.cs.uiuc.edu/mailman/listinfo/lldb-dev
> >>
> >>
> >>
> >> --
> >> Eran Ifrah
> >> Author of codelite, a cross platform open source C/C++ IDE:
> http://www.codelite.org
> >> wxCrafter, a wxWidgets RAD: http://wxcrafter.codelite.org
> >
> >
> >
> > --
> > Eran Ifrah
> > Author of codelite, a cross platform open source C/C++ IDE:
> http://www.codelite.org
> > wxCrafter, a wxWidgets RAD: http://wxcrafter.codelite.org
> >
> >
> >
> > --
> > Eran Ifrah
> > Author of codelite, a cross platform open source C/C++ IDE:
> http://www.codelite.org
> > wxCrafter, a wxWidgets RAD: http://wxcrafter.codelite.org
> > _______________________________________________
> > lldb-dev mailing list
> > lldb-dev at cs.uiuc.edu
> > http://lists.cs.uiuc.edu/mailman/listinfo/lldb-dev
>
>
--
Eran Ifrah
Author of codelite, a cross platform open source C/C++ IDE:
http://www.codelite.org
wxCrafter, a wxWidgets RAD: http://wxcrafter.codelite.org
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