[cfe-users] Parsing C code looking for Basic Blocks

[Harald Servat]

El dt 19 de 03 de 2013 a les 10:42 -0700, en/na Anna Zaks va escriure:
> 
> On Mar 19, 2013, at 8:43 AM, Harald Servat <harald.servat at bsc.es>
> wrote:
> 
> > El dt 19 de 03 de 2013 a les 12:43 +0100, en/na Harald Servat va
> > escriure:
> > > Dear list,
> > > 
> > >  I'm a newcommer to Clang/LLVM and I'm not sure whether this is
> > > the
> > > correct place to ask this topic. If it's not, would you mind to
> > > point me
> > > to the correct place/list?
> > > 
> > >  I'm looking for a mechanism to detect basic blocks in C codes
> > > (optionally C++, and eventually Fortran, in a future). I'm
> > > wondering
> > > whether how can Clang help me? Is it an appropriate tool for doing
> > > such
> > > thing? I'm not looking for something very difficult (I think). 
> > > 
> > >  Imagine I have the following code (line numbering on the left,
> > > source
> > > code on the right)
> > > 
> > > 01: void foo(void)
> > > 02: {
> > > 03:    int a = 10;
> > > 04:    int b = 11;
> > > 05:    if (a > b)
> > > 06:    {
> > > 07:       printf ("a is greater than b\n");
> > > 08:    }
> > > 09:    else
> > > 10:   {
> > > 11:      printf ("b is greater or equal than a\n");
> > > 12:   }
> > > 13: }
> > > 
> > >  I'd like to have a obtain a list of pairs that delimit the basic
> > > blocks of the code. For the previous example, for instance it
> > > should
> > > return something like : [01-05], [06-08], [10-12]. 
> > > 
> > >  Is there any Clang mechanism to provide such information? If not,
> > > is
> > > it possible to do it through Clang?
> > > 
> > > Thank you very much!
> > > 
> > > 
> > > 
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> > 
> > Hello,
> > 
> >  I found the following command exceptionally useful for the purposes
> > I
> > wanted:
> > 
> >    clang -cc1 -ast-dump file.c
> > 
> > 
> This would dump AST, not Basic Blocks from Control Flow Graph. Clang
> does have CFG as well. 
> To view/dump CFG use debug.ViewCFG or debug.DumpCFG checkers: 
> $ clang -cc1 -analyze -analyzer-checker=debug.Dump/CFG test.c
> 
> 
> Note, this is a debugging facility and not a user feature of clang, so
> the interface is not guaranteed to be stable.

  Thank you for pointing that Anna. I've tried what you mention, and now
I realize that I was looking for the AST tree instead of basic blocks.
To generate a list of basic blocks you need to compile the file and I
don't want to compile it fully (i.e. I don't want to generate an object
file). I simply want to do some kind of code blocks breakdown, and thus
-ast-dump fulfills my needs.

Best regards.





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intended recipient, you are strictly prohibited from disclosing,
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received this communication in error, please notify the sender and
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