[llvm-dev] Questions after completed Kaleidoscope Chapter 1

Praveen Velliengiri via llvm-dev
Mon, 16 Sep 2019 11:26:32 -0000

Hi Bjoern,
Only mangling names should not work, in other words you have to mangle the
name according to your platform and intern the symbol to the Execution
session. ORC plays with interned symbols.
There is an overload of lookup which receives the mangled name and intern
it internally in it's implementation. So either way can work for you!

The Symbol name is the function name - So try just lookup("helloORC").

Let me know, if it solves the problem.

Cheers,
Praveen


On Mon, 16 Sep 2019 at 15:59, Gaier, Bjoern <Bjoern.Gaier at horiba.com>
wrote:

> Hey Praveen – and everyone else,
>
>
>
> For 1.)
>
> In my “Main.cpp” file I used
>
> int (*function)() = (int(*)())jit->lookup("?helloOrc@@YAHXZ");
>
>
>
> While the lookup looked like that:
>
> uintptr_t lookup(StringRef Name)
>
> {
>
>        auto result =
this->es.lookup({&this->es.getMainJITDylib()}, this
> ->mangle(Name.str()));
>
>        if(result)
>
>        {
>
>               return result->getAddress();
>
>        }
>
>
>
>        return 0x0;
>
> }
>
> Basically – it is the code from the tutorial, besides I wanted it to
> return an unintpr_t.
> Anyway, if I remove “this->mangle(Name.str())” and use “Name.str()”
> instead - then it is still working. This is why I wonder, why that call is
> important.
>
>
>
> A call like:
> int (*function)() = (int(*)())jit->lookup("int helloOrc()");
> Never worked.
>
>
>
> For 2.)
> I solved the problem by exporting the missing symbols, I just wanted to
> understand if the error is coming from the “DynamicLibrarySearchGenerator”
> and if I can silence it to keep my console output clean.
>
>
>
> For 3.)
>
> I understand that!
>
>
>
> Thank you so much for this x3
>
>
>
> Kind greetings
>
> Björn
>
>
>
> *From:* Praveen Velliengiri <praveenvelliengiri at gmail.com>
> *Sent:* Donnerstag, 12. September 2019 19:51
> *To:* David Blaikie <dblaikie at gmail.com>
> *Cc:* Gaier, Bjoern <Bjoern.Gaier at horiba.com>; Lang Hames <
> lhames at gmail.com>; llvm-dev <llvm-dev at lists.llvm.org>
> *Subject:* Re: [llvm-dev] Questions after completed Kaleidoscope Chapter 1
>
>
>
> Hi Bjoren,
>
>
>
> For question 1:
>
> As you mentioned, it is used to mangle to the symbol name and interning
> them, So ORC can find them at runtime in one of the JITDylibs. It would be
> helpful to know what you tried? (please attach code lines).
>
>
>
> For question 2:
>
> I guess you might be missing to link libraries that your program depend
> on, you can do that via setting up your dynamiclibrary search generator or
> getCurrentProcess symbols. Plus, Why do you want to hide them, it is an
> error?
>
>
>
> For question 3:
>
> Currently, every symbol whether it is added via generator or not, must be
> defined in a JITDylib. It is more of a design choice, it makes
> implementation and resolution logic much easier within ORC.
>
>
>
> Thanks
>
> Praveen
>
>
>
>
>
> On Thu, 12 Sep 2019 at 22:56, David Blaikie via llvm-dev <
> llvm-dev at lists.llvm.org> wrote:
>
> (adding Lang Hames, Orcish Scientist, for Orc-related queries)
>
> On Thu, Sep 12, 2019 at 3:23 AM Gaier, Bjoern via llvm-dev
> <llvm-dev at lists.llvm.org> wrote:
> >
> > Hello there,
> >
> >
> >
> > I finished Chapter 1 of the Kaleidoscope tutorial for using the Orc
JIT
> API. I played around with some things and ended with some questions.
> >
> >
> >
> > What is the use of “MangleAndInterner”?
> > I read it is used to mangle the name for the lookup search, but I seem
> to be not able to use it correctly. In my first attempt I used the mangled
> name of my function “?helloOrc@@YAHXZ” with the lookup method – that
> worked.
> >
> > Now I tried “int helloOrc()” and it failed/did not found the function.
> Then I tried “?helloOrc@@YAHXZ” again but removed the use of the
> “MangleAndInterner” instance – that worked again.
> >
> > What is that instance used for?
> >
> >
> >
> > JIT session error
> >
> > When I first run the JIT, the message “JIT session error: Symbols not
> found: { __security_check_cookie, __security_cookie }” was printed into the
> console.
> >
> > Origin
> > Is that message coming from "DynamicLibrarySearchGenerator”?
> >
> >
> >
> > Redirect
> > Can I somehow redirect this message to a string or something, or
silence
> it? I want to keep my console output clean.
> >
> >
> >
> > Generator function
> >
> > Why does the generator function looks like this:
“SymbolNameSet(JITDylib
> &Parent, const SymbolNameSet &Names)”?
> >
> > I understood, that the “Parent” will be the value from
> “ES.getMainJITDylib()” while “Names” will have the names that should be
> resolved. I saw an implementation for the Generator function that kinda
> looked like that:
> > {
> >
> >       orc::SymbolNameSet Added;
> >
> >       orc::SymbolMap     NewSymbols;
> >
> >
> >
> >       for(auto &Name : Names)
> >
> >       {
> >
> >             Added.insert(Name);
> >
> >             NewSymbols[Name] = //Something
> >
> >       }
> >
> >
> >
> >       Parent.define(absoluteSymbols(std::move(NewSymbols)));
> >
> >       return Added;
> >
> > }
> >
> >
> >
> > I understood that “SymbolMap NewSymbols” will store a pair of name and
> the address to resolve – but why do I tell the JITDylib about this?
> > And why do I also keep a map of the symbols I added and have to return
> them? (SymbolNameSet Added)
> >
> >
> >
> > I hope my questions are not too stupid and that someone can help me
with
> that!
> >
> > Thank you a lot x3
> >
> >
> >
> > Kind greetings
> >
> > Björn
> >
> > Als GmbH eingetragen im Handelsregister Bad Homburg v.d.H. HRB 9816,
> USt.ID-Nr. DE 114 165 789 Geschäftsführer: Dr. Hiroshi Nakamura, Dr. Robert
> Plank, Markus Bode, Heiko Lampert, Takashi Nagano, Takeshi Fukushima.
> Junichi Tajika
> > _______________________________________________
> > LLVM Developers mailing list
> > llvm-dev at lists.llvm.org
> > https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
> _______________________________________________
> LLVM Developers mailing list
> llvm-dev at lists.llvm.org
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>
> Als GmbH eingetragen im Handelsregister Bad Homburg v.d.H. HRB 9816,
> USt.ID-Nr. DE 114 165 789 Geschäftsführer: Dr. Hiroshi Nakamura, Dr. Robert
> Plank, Markus Bode, Heiko Lampert, Takashi Nagano, Takeshi Fukushima.
> Junichi Tajika
>
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