llvm dev - Nov 2007 - [LLVMdev] 'Implementing a language with LLVM' tutorial

Hi All,

LLVM has long needed a tutorial for people who are interested in using  
it to implement their favorite language and to demonstrate how to use  
the JIT.  To help solve this, I've put together a little tutorial that  
runs through the implementation and extension of a toy language here:

   http://llvm.org/docs/tutorial/

At this point, the tutorial is feature complete, but might still need  
some final editing.  Before I try to get other sites to link to it, I  
thought it would be good to get some more eyeballs on it and get some  
thoughts and feedback from you.

Anyone have thoughts or feedback? :)

-Chris

> Hi All,
>
> LLVM has long needed a tutorial for people who are interested in using
> it to implement their favorite language and to demonstrate how to use
> the JIT.  To help solve this, I've put together a little tutorial that
> runs through the implementation and extension of a toy language here:
>
>   http://llvm.org/docs/tutorial/
>
> At this point, the tutorial is feature complete, but might still need
> some final editing.  Before I try to get other sites to link to it, I
> thought it would be good to get some more eyeballs on it and get some
> thoughts and feedback from you.
>
> Anyone have thoughts or feedback? :)
Nice job. The only bit that is not immediately clear is the 'Proto' 
variable, but is clear when looking through the code at the end of the page.

Could do with a link to the LLVMBuilder class reference material.

Thanks,

Aaron

On 11/5/07, Chris Lattner <clattner at apple.com>
wrote:
> Hi All,
Hi,
>
>    http://llvm.org/docs/tutorial/
Very interesting tutorial, reading it now :)
> Anyone have thoughts or feedback? :)
There's a typo in http://llvm.org/docs/tutorial/LangImpl5.html
"the Phi node expects to have an extry" s/extry/entry/

Best regards,
Edwin

On 11/5/07, Chris Lattner <clattner at apple.com> wrote:
>    http://llvm.org/docs/tutorial/
> Anyone have thoughts or feedback? :)
Found some typos in LangImpl2.html:

/// identifierexpr
///   ::= identifer
///   ::= identifer '(' expression* ')'


HTH,
Kevin André

Chris Lattner wrote:
> Hi All,
> 
> LLVM has long needed a tutorial for people who are interested in using  
> it to implement their favorite language and to demonstrate how to use  
> the JIT.  To help solve this, I've put together a little tutorial that
> runs through the implementation and extension of a toy language here:
> 
>    http://llvm.org/docs/tutorial/
A big thanks for it.  I had just a glance on it (some I may be wrong) 
but I would find nice an exact explanation of 
llvm/examples/HowToUseJIT/ in particular it seems that the exact way of 
calling the just JIT-ed code is skipped in this tutorial. Maybe I missed 
some link.

Again, a big thanks to Chris !


-- 
Basile STARYNKEVITCH         http://starynkevitch.net/Basile/
email: basile<at>starynkevitch<dot>net mobile: +33 6 8501 2359
8, rue de la Faiencerie, 92340 Bourg La Reine, France
*** opinions {are only mines, sont seulement les miennes} ***

Nice work, Chris!  This is a much needed tutorial.  Some comments:

-- It would be helpful to add some navigation links at the top and  
bottom of the pages. 

-- Not clear why PrototypeAST::Codegen returns a Function* instead of  
a Value* like the other CodeGen methods?

-- It can be convenient to use Visitor methods on the AST classes for  
code generation, instead of hard-coding the CodeGen methods into the  
AST classes.  Many languages will need other traversals besides the  
CodeGen operations, e.g., for type checking, class layout, etc.

-- In the optimization section, how much code size reduction have you  
seen in practice by doing constant folding in the LLVMFoldingBuilder  
(instead of just letting the later optimization pass take care of it)?

-- One of the harder parts is generating type declarations correctly  
for recursively connected types (e.g., for classes).  Without  
extending Kaleidoscope, it would be be helpful to add a link to the  
Programmers Manual section on recursive type construction.


--Vikram
http://www.cs.uiuc.edu/~vadve
http://llvm.org/


On Nov 5, 2007, at 1:14 AM, Chris Lattner wrote:
> Hi All,
>
> LLVM has long needed a tutorial for people who are interested in using
> it to implement their favorite language and to demonstrate how to use
> the JIT.  To help solve this, I've put together a little tutorial that
> runs through the implementation and extension of a toy language here:
>
>    http://llvm.org/docs/tutorial/
>
> At this point, the tutorial is feature complete, but might still need
> some final editing.  Before I try to get other sites to link to it, I
> thought it would be good to get some more eyeballs on it and get some
> thoughts and feedback from you.
>
> Anyone have thoughts or feedback? :)
>
> -Chris
> _______________________________________________
> LLVM Developers mailing list
> LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev
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Hi Chris,

edwintorok at gmail.com wrote:
> On 11/5/07, Chris Lattner <clattner at apple.com> wrote:
> >    http://llvm.org/docs/tutorial/
> 
> There's a typo in http://llvm.org/docs/tutorial/LangImpl5.html
> "the Phi node expects to have an extry" s/extry/entry/
And elsewhere it has "an function" as the output of a.out despite the
source saying "a function".

Cheers,


Ralph.

On Mon, 5 Nov 2007, [ISO-8859-1] T�r�k Edvin wrote:
>> Anyone have thoughts or feedback? :)
>
> There's a typo in http://llvm.org/docs/tutorial/LangImpl5.html
> "the Phi node expects to have an extry" s/extry/entry/
Fixed, thanks!

On Mon, 5 Nov 2007, HyperQuantum wrote:
> Found some typos in LangImpl2.html:
> /// identifierexpr
> ///   ::= identifer
> ///   ::= identifer '(' expression* ')'
Fixed, thanks!

On Mon, 5 Nov 2007, Basile STARYNKEVITCH wrote:
> A big thanks for it.  I had just a glance on it (some I may be wrong)
> but I would find nice an exact explanation of
> llvm/examples/HowToUseJIT/ in particular it seems that the exact way of
> calling the just JIT-ed code is skipped in this tutorial. Maybe I missed
> some link.
I think that is is covered here (it's only 3 lines of code, so it's easy
to miss ;-):
http://llvm.org/docs/tutorial/LangImpl4.html#jit

Please let me know if it is unclear.

On Mon, 5 Nov 2007, Ralph Corderoy wrote:
> And elsewhere it has "an function" as the output of a.out despite
the
> source saying "a function".
Fixed, thanks!

-Chris

-- 
http://nondot.org/sabre/
http://llvm.org/

On Mon, 5 Nov 2007, Aaron Gray wrote:
>> Anyone have thoughts or feedback? :)
>
> Nice job. The only bit that is not immediately clear is the 'Proto'
> variable, but is clear when looking through the code at the end of the
page.
Where in the tutorial?  What would you suggest that I say?
> Could do with a link to the LLVMBuilder class reference material.
I added a link to the doxygen info, thanks!

-Chris

-- 
http://nondot.org/sabre/
http://llvm.org/

On Mon, 5 Nov 2007, Vikram S. Adve wrote:
> -- It would be helpful to add some navigation links at the top and bottom
of
> the pages.
I added a TOC to each chapter, thanks.
> -- Not clear why PrototypeAST::Codegen returns a Function* instead of a 
> Value* like the other CodeGen methods?
I clarified this in the text.  The short version is that PrototypeAST 
doesn't correspond to an expression value.
> -- It can be convenient to use Visitor methods on the AST classes for code 
> generation, instead of hard-coding the CodeGen methods into the AST
classes.
> Many languages will need other traversals besides the CodeGen operations, 
> e.g., for type checking, class layout, etc.
Yep, the tutorial also leaks memory, uses global variables, and commits a 
number of other sins against good software engineering practice.  However, 
I added a mention of the possibility of using a visitor to the text.
> -- In the optimization section, how much code size reduction have you seen
in
> practice by doing constant folding in the LLVMFoldingBuilder (instead of
just
> letting the later optimization pass take care of it)?
Depends on the language.  For C, it can be significant.  In any case, 
there is no reason not to use the folding builder, so it doesn't hurt 
anything.
> -- One of the harder parts is generating type declarations correctly for 
> recursively connected types (e.g., for classes).  Without extending 
> Kaleidoscope, it would be be helpful to add a link to the Programmers
Manual
> section on recursive type construction.
I added a link to chapter 8, thanks for the feedback!

-Chris
>
> On Nov 5, 2007, at 1:14 AM, Chris Lattner wrote:
>
>>  Hi All,
>> 
>>  LLVM has long needed a tutorial for people who are interested in using
>>  it to implement their favorite language and to demonstrate how to use
>>  the JIT.  To help solve this, I've put together a little tutorial
that
>>  runs through the implementation and extension of a toy language here:
>> 
>>     http://llvm.org/docs/tutorial/
>> 
>>  At this point, the tutorial is feature complete, but might still need
>>  some final editing.  Before I try to get other sites to link to it, I
>>  thought it would be good to get some more eyeballs on it and get some
>>  thoughts and feedback from you.
>> 
>>  Anyone have thoughts or feedback? :)
>> 
>>  -Chris
>>  _______________________________________________
>>  LLVM Developers mailing list
>>  LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
>>  http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev
>
>
>
-Chris

-- 
http://nondot.org/sabre/
http://llvm.org/

Hi Chris,

I edited "The basic language, with its lexer" somewhat and I am
attaching a .html file. This is simply spelling/grammar editing and not
content. 

It includes a few small changes to things like - ending a sentence with
a noun and starting the next sentence with the same noun, clarifying
some statements, not using "and" too many times in a sentence...little
things like that.

A simple diff should show the changes. Please let me know if this format
(ie. html file) is acceptable for your use. I don't think I changed
anything too drastically, but please let me know if I took too many
liberties. You may also tell me not to be so picky, if you like ;)

Thanks,
K.Wilson

P.S. Good work. This is a well written and much needed tutorial.


On Sun, 2007-11-04 at 23:14 -0800, Chris Lattner wrote:
> Hi All,
> 
> LLVM has long needed a tutorial for people who are interested in using  
> it to implement their favorite language and to demonstrate how to use  
> the JIT.  To help solve this, I've put together a little tutorial that
> runs through the implementation and extension of a toy language here:
> 
>    http://llvm.org/docs/tutorial/
> 
> At this point, the tutorial is feature complete, but might still need  
> some final editing.  Before I try to get other sites to link to it, I  
> thought it would be good to get some more eyeballs on it and get some  
> thoughts and feedback from you.
> 
> Anyone have thoughts or feedback? :)
> 
> -Chris
> _______________________________________________
> LLVM Developers mailing list
> LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev
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On Mon, 5 Nov 2007, Kelly Wilson wrote:
> I edited "The basic language, with its lexer" somewhat and I am
> attaching a .html file. This is simply spelling/grammar editing and not
> content.
Thanks, I merged them in!
> A simple diff should show the changes. Please let me know if this format
> (ie. html file) is acceptable for your use. I don't think I changed
> anything too drastically, but please let me know if I took too many
> liberties. You may also tell me not to be so picky, if you like ;)
All the changes you made look great, I appreciate it.  If you are 
interested in making future changes, please send me a diff of the change 
you make.  This makes it easier for me, because I don't know which version 
of the file you started from, making it harder to pull the difference out 
on my end.

Thanks again!

-Chris

-- 
http://nondot.org/sabre/
http://llvm.org/

Hey Chris:

Here are the diffs for the next few chapters of the tutorial that I have
edited. Please note that there is one recurring fix (straight-forward is
changed to straightforward). Once again, these are simple changes, not
including any real content changes.

Thanks,
K.Wilson


On Sun, 2007-11-04 at 23:14 -0800, Chris Lattner wrote:
> Hi All,
> 
> LLVM has long needed a tutorial for people who are interested in using  
> it to implement their favorite language and to demonstrate how to use  
> the JIT.  To help solve this, I've put together a little tutorial that
> runs through the implementation and extension of a toy language here:
> 
>    http://llvm.org/docs/tutorial/
> 
> At this point, the tutorial is feature complete, but might still need  
> some final editing.  Before I try to get other sites to link to it, I  
> thought it would be good to get some more eyeballs on it and get some  
> thoughts and feedback from you.
> 
> Anyone have thoughts or feedback? :)
> 
> -Chris
> _______________________________________________
> LLVM Developers mailing list
> LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev
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On Nov 11, 2007, at 2:41 PM, Kelly Wilson wrote:
> Hey Chris:
>
> Here are the diffs for the next few chapters of the tutorial that I  
> have
> edited.
Nice!  You are an excellent editor, I'm impressed.  I committed these  
without any changes here:
http://lists.cs.uiuc.edu/pipermail/llvm-commits/Week-of-Mon-20071112/055566.html

Thank you for the help with this.
> Please note that there is one recurring fix (straight-forward is
> changed to straightforward).
Noted, I'll try to teach my fingers :)

-Chris