[lldb-dev] Help with C++ API

[Jakob Leben]

On Wed, Aug 28, 2013 at 2:15 PM, Enrico Granata <egranata at apple.com> wrote:
> I think such a visualization would be highly inconvenient for most users
> most of the time, much as you do not want to see a char* so much as an array
> of chars but rather as a logical “string”, the same is true of std::string
> Also, if you know the layout of the string class, you can directly access
> the data buffer and read the individual bytes out of memory, which is also a
> discouraging argument from going down the synthetic children route: the
> added value compared to the actual type layout is quite low.
> This is why LLDB vends a summary instead of synthetic children.

I see you point.

I am approaching the issue from another perspective though: I am
building an application with the concept of "programming-model-aware
debugging", specifically data-flow programming model. I found the LLDB
C++ API valuable, because it allows me to easily build an application
that attaches to another process which performs processing of a
data-flow graph (think multimedia processing) and displays the
processing behavior in a graphical way. So I consider the LLDB C++ API
as a convenient utility and abstraction on top of
operating-system-provided debugging facilities, but for other purpose
than implementing a classical command-line debugger. Instead, it is
used as a utility to examine another program's state and data in a
convenient way.

Therefore, in my use case I need to access the *actual* data to
display it to the end-user in any arbitrary way that LLDB API should
never need to assume in itself. Providing a summary/value of a data
structure's contents as a string (returned by GetSummary() or
GetValue()) is an example of such an assumption.