[lldb-dev] debug server help

Carlo Kok ck at remobjects.com
Wed Sep 19 02:10:36 PDT 2012

Op 18-9-2012 23:25, Greg Clayton schreef:
> On Sep 18, 2012, at 1:56 PM, Carlo Kok <ck at remobjects.com> wrote:
>> Op 18-9-2012 21:54, Carlo Kok schreef:
>>> Op 18-9-2012 20:06, Greg Clayton schreef:
>>>> I removed all uses of "%z" modifiers in our printf format strings in
>>>> top of tree. Merge top of tree over to get the fixes:
>>> Thanks for the help Greg (and João Matos). Limited remote debugging
>>> works now on Windows (after my latest commit), start, continue,
>>> breakpoint, kill and event handling (Through code only, the driver is
>>> still not working on Windows).
>> I noticed it transfers about 16mb worth of data (for a single bp on
>> main in a printf("hello"); sleep() function). What options do I
>> have to optimize this? It seems to be doing lots of "Read memory"
>> from within the symbol loading code (and if I kill the process
>> while it does it it sigsegv-s). I couldn't find a "need symbols for
>> dylib/file X" event I could hook up to (i can get the files over
>> and store them locally that way it could load it from disk)
> Yes, all shared libraries are being read from memory.
> Platforms do have the ability to set an sysroot:
> (lldb) platform select --sysroot \path\to\macosx\sysroot
> remote-macosx
> If you make a local copy of the shared libraries from your remote Mac
> OS (copy /usr/bin/* /usr/lib/* /System/Library/Frameworks/*
> /System/Library/PrivateFrameworks/* and what ever else you neeed)
> into a local directory like "\path\to\macosx\sysroot", then you wil
> avoid this issue. So when we go asking for "/usr/lib/dyld" we will
> look in "\path\to\macosx\sysroot\usr\lib\dyld". This is the real
> reason we want to have a platform connection: so we can download SDK
> files and cache them locally. For now we will need to just let it
> copy stuff.
> The other way to do this, is ask users to mount the remote MacOSX
> root partition so that it can be accessed locally. If you enable
> windows sharing on your remote Mac, you should be able to connect to
> it, and then just give that path for the "--sysroot". We don't expose
> the platforms as objects through the public API at the moment, but
> you can easily just execute the command:
> m_debugger.HandleCommand ("platform select --sysroot
> \path\to\macosx\sysroot remote-macosx");
> m_debugger.CreateTarget(....)
> Does that make sense?

it does. First i want to try to make this work dynamically though (we 
have a "server app" like your "remote" host) that has the ability to 
download files to the computer on demand. I'm thinking I'll subclass 
"PlatformWindows" and override:

PlatformWindows::ResolveExecutable (const FileSpec &exe_file,
                                     const ArchSpec &exe_arch,
                                     lldb::ModuleSP &exe_module_sp,
                                     const FileSpecList 

That triggers for each file, and download (if possible) from there.

Forcing my users to download all files manually does not sound like a 
practical option for me.

Thanks for the Help,

Carlo Kok

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